.NET Elevation of Privilege Vulnerability

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

A crafted X-Forwarded-Prefix can inject cookie path delimiters unless PathBase-derived cookie paths percent-encode semicolons.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/508

CVSS Details

- Version: 3.1 - Severity: Medium - Score: 6.1 (base score) - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N/E:U/RL:O/RC:C - Weakness: CWE-116

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-rc.1.23421.29, <= 8.0.33 | 8.0.34

.NET 9.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23

.NET 10.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-109476

Acknowledgements

- Raffaello Tamagnini

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

Processing comma-separated HTTP header values can cause excessive allocations and resource exhaustion.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/515

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-407

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34

.NET 9.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-arm | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-arm | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-arm64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-arm64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-arm64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-x64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-x64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.linux-x64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-arm64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-arm64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-arm64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-x64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-x64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.osx-x64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-arm64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-arm64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-arm64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x64 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x64 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x64 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x86 | = 9.0.0-preview.1.24081.5 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x86 | = 9.0.0-preview.2.24128.4 | 9.0.0-preview.4.24267.6 Microsoft.AspNetCore.App.Runtime.win-x86 | = 9.0.0-preview.3.24172.13 | 9.0.0-preview.4.24267.6

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-109478

Acknowledgements

- Matteo Panzeri

Revisions

V1.0 (November 10, 2026): Advisory published.

.NET Denial of Service Vulnerability

.NET Elevation of Privilege Vulnerability

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

SignalR connections are not consistently bound to the identity negotiated at connection establishment, allowing injected messages to execute Hub invocations as the victim.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/504

CVSS Details

- Version: 3.1 - Severity: Critical - Score: 9.0 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness: CWE-863

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

ASP.NET Core 2.3 - standalone packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.Http.Connections | >= 1.2.0, <= 1.2.13 | 1.2.14

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34

.NET 9.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23

.NET 10.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. After updating standalone packages, rebuild and redeploy affected applications, including framework-dependent applications; restarting alone does not replace app-local packages. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-114146

Acknowledgements

- Mika Vehns with MIVE GmbH - Lucas Gabriel - hsuan0223x - Mariusz Maik - Pocas (Jeongwon Jo) - Grace Chapel - Jacob Keith with Keith Systems - Weeraphat Srisutham - Kevin Gosse - Artur Stetsko - Yudai Shibata - 71C4 - Attila Csatadi of ZeroDayBugs.com - Vu Van Tien ( @n0Be3r )

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

SignalR Redis scale-out can mishandle case-mismatched group removal and leave subscriptions in a state that permits persistent resource amplification and denial of service.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/509

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-401

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

8.0 - standalone packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34

9.0 - standalone packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23

10.0 - standalone packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15

11.0 - standalone packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.SignalR.StackExchangeRedis | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34

.NET 9.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23

.NET 10.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Compare the deployed ASP.NET Core runtime and the application's resolved Microsoft.AspNetCore.SignalR.StackExchangeRedis package version with the affected ranges above. Self-contained applications include their own runtime.

<a name="how-fix"></a>How do I fix the issue?

Update both the ASP.NET Core runtime and the Microsoft.AspNetCore.SignalR.StackExchangeRedis package to the applicable patched versions above. Restart affected framework-dependent applications after installing the runtime update. Rebuild and redeploy applications after updating the package; self-contained applications must also be rebuilt with the patched runtime. Updating a machine-wide runtime or SDK alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-114147

Acknowledgements

- 71C4 with ARPSEC - 71C4

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

Multipart form processing can bypass the configured header-count limit and consume excessive resources.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/511

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-770

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0-preview.1.23112.2, <= 8.0.33 | 8.0.34

.NET 9.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23

.NET 10.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Standalone WebUtilities delivery

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.WebUtilities | >= 8.0.0-preview.5.23302.2, <= 8.0.33 | 8.0.34 Microsoft.AspNetCore.WebUtilities | >= 9.0.0-preview.1.24081.5, <= 9.0.22 | 9.0.23 Microsoft.AspNetCore.WebUtilities | >= 10.0.0-preview.1.25120.3, <= 10.0.14 | 10.0.15 Microsoft.AspNetCore.WebUtilities | >= 11.0.0-preview.1.26104.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. After updating standalone packages, rebuild and redeploy affected applications, including framework-dependent applications; restarting alone does not replace app-local packages. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-114149

Acknowledgements

- n0irx

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

The Blazor/SignalR /blazor/refresh path can accept a cross-site request that binds a victim's authenticated principal to an attacker-owned circuit.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/506

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness: CWE-352

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.6.26359.118, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-109481

Acknowledgements

- Derek Haber with Armadin - Anonymous - Artur Stetsko - s3zer0 - Leonardo Souza with Delfia - Attila.Cs(zerodaybugs.com) with https://zerodaybugs.com/

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

PathString.StartsWithSegments can mishandle percent-encoded backslashes and permit authorization checks to match an unintended path.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/510

CVSS Details

- Version: 3.1 - Severity: Medium - Score: 6.5 (base score) - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N/E:U/RL:O/RC:C - Weakness: CWE-41

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-114156

Acknowledgements

- Anonymous

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

A reused ResponseBufferingStream can retain pooled tail memory and expose response-body data from another request through HTTP logging.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/514

CVSS Details

- Version: 3.1 - Severity: Medium - Score: 5.9 (base score) - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C - Weakness: CWE-908

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.2.26159.112, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-114150

Acknowledgements

- Kevin Gosse

Revisions

V1.0 (November 10, 2026): Advisory published.

.NET Elevation of Privilege Vulnerability

.NET Security Feature Bypass Vulnerability

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

Minimal API validation repeatedly copies a growing validation-error dictionary, allowing attacker-controlled collections to trigger quadratic CPU work after the client disconnects.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/505

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-407

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0

Standalone validation delivery

Package | Affected version | Patched version --- | --- | --- Microsoft.Extensions.Validation | >= 11.0.0-rc.1.26425.128, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-118749

Acknowledgements

- Alejandro Pacheco - Artur Stetsko

Revisions

V1.0 (November 10, 2026): Advisory published.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core. This advisory provides guidance on updating affected applications and components.

Blazor static-SSR client validation retains attacker-controlled rendered field names in an unbounded singleton cache, allowing remote process memory exhaustion.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/516

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-770

Affected Platforms

- Platforms: Windows, Linux, macOS - Architectures: All

<a name="affected-packages"></a>Affected Packages

The tables list affected version ranges and fixed package versions. Runtime and standalone deliveries are listed separately.

.NET 11.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 11.0.0-preview.7.26381.103, <= 11.0.0-rc.3.26522.148 | 11.0.0

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

Check the deployed runtime and application package versions against the affected ranges above. Self-contained applications include their own runtime; updating a machine-wide runtime does not replace it.

<a name="how-fix"></a>How do I fix the issue?

Install the applicable runtime or update each independently referenced package to the fixed version above. Restart applications. Rebuild and redeploy self-contained applications; updating a machine-wide runtime does not replace their embedded runtime. An SDK update alone does not update an application's standalone package references.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-118748

Acknowledgements

- Artur Stetsko - Alejandro Pacheco

Revisions

V1.0 (November 10, 2026): Advisory published.

.NET Denial of Service Vulnerability

Summary

Out-of-bounds Write vulnerability in the bundled Brotli decoder in yjh0502 erl-brotli allows an attacker who supplies a crafted Brotli-compressed stream to brotli:decode/1 to corrupt decoder state memory, disclose memory contents, crash the Erlang VM, or potentially execute code.

erl-brotli compiles its own copy of the Google Brotli C sources under csrc into a NIF, and brotlidecoderdecompressstream in csrc/brotlinif.c hands the input to BrotliDecoderDecompressStream. In csrc/dec/decode.c, DecodeBlockTypeAndLength returns false for a block switch in a category with at most one block type, and the non-streaming callers DecodeLiteralBlockSwitch, DecodeCommandBlockSwitch and DecodeDistanceBlockSwitch discard that result, so decoding continues with inconsistent state. The decoder runs inside a NIF, so memory corruption or a crash takes down the whole VM rather than the calling process. Because the package carries its own copy of the library, the Brotli version installed on the host does not matter.

This issue affects brotli: from 0.3.0 before 0.3.4.

Impact

An attacker who can get an application to decode a Brotli stream they control, for example an HTTP client that decompresses Content-Encoding: br responses with this package, can crash the Erlang VM and potentially run code inside it.

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core SignalR and Blazor Server. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A denial of service vulnerability exists in the MessagePack hub protocol used by SignalR and Blazor Server where an attacker can send deeply-nested MessagePack arrays to cause a stack overflow, resulting in a denial of service.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/405

Affected Platforms

- Platforms: All - Architectures: All

<a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below

<a name=".NET 10"></a>.NET 10 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.win-arm | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.8 | 10.0.9 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.8 | 10.0.9

<a name=".NET 10 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 10) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 10.0.0, <= 10.0.8 | 10.0.9

<a name=".NET 9"></a>.NET 9 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.win-arm | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.16 | 9.0.17 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.16 | 9.0.17

<a name=".NET 9 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 9) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 9.0.0, <= 9.0.16 | 9.0.17

<a name=".NET 8"></a>.NET 8 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.win-arm | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.27 | 8.0.28 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.27 | 8.0.28

<a name=".NET 8 SignalR"></a>Microsoft.AspNetCore.SignalR.Protocols.MessagePack (.NET 8) Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 8.0.0, <= 8.0.27 | 8.0.28

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

If using a package listed in affected packages, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

1. To fix the issue please install the latest version of .NET 10.0, .NET 9.0, or .NET 8.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs. 2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

If you're using .NET 8.0, you should download and install .NET 8.0.28 Runtime or .NET 8.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/8.0. If you're using .NET 9.0, you should download and install .NET 9.0.17 Runtime or .NET 9.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/9.0. If you're using .NET 10.0, you should download and install .NET 10.0.9 Runtime or .NET 10.0.xxx SDK from https://dotnet.microsoft.com/download/dotnet-core/10.0.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/aspnetcore. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Acknowledgements

Anonymous

.NET Tampering Vulnerability

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.NET Tampering Vulnerability

.NET Denial of Service Vulnerability

Microsoft Security Advisory CVE-2026-56170 – .NET Denial of Service Vulnerability

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in ASP.NET Core SignalR (Microsoft.AspNetCore.App.Runtime). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

A denial of service vulnerability exists in ASP.NET Core SignalR in .NET 8, .NET 9, and .NET 10. Stateful reconnect can be leveraged by an attacker to deny service to other users.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/TBD

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C - Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

Affected Platforms

- Platforms: All - Architectures: All

Mitigation Factors

Your ASP.NET Core app is only affected if it uses SignalR with stateful reconnect enabled.

<a name="affected-packages"></a>Affected Packages The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below

<a name=".NET 10.0"></a>.NET 10.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.win-arm | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.5 | 10.0.6 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.5 | 10.0.6

<a name=".NET 9.0"></a>.NET 9.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.win-arm | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.14 | 9.0.15 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.14 | 9.0.15

<a name=".NET 8.0"></a>.NET 8.0 Package name | Affected version | Patched version ------------ | ---------------- | ------------------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.linux-arm64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.linux-musl-arm | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.linux-musl-arm64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.linux-musl-x64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.linux-x64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.osx-arm64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.osx-x64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.win-arm | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.win-arm64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.win-x64 | >= 8.0.0, <= 8.0.25 | 8.0.26 Microsoft.AspNetCore.App.Runtime.win-x86 | >= 8.0.0, <= 8.0.25 | 8.0.26

Advisory FAQ

<a name="how-affected"></a>How do I know if I am affected?

If using a package listed in affected packages, you're exposed to the vulnerability.

<a name="how-fix"></a>How do I fix the issue?

1. To fix the issue please install the latest version of .NET. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs. 2. If your application references the vulnerable nuget package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

Other Information

Reporting Security Issues

If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.

Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.

Support

You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.

Disclaimer

The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

External Links

CVE-2026-56170

Acknowledgements

Ky0toFu

Revisions

V1.0 (July 14, 2026): Advisory published.

.NET Framework Denial of Service Vulnerability