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.
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.
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.