GHSA-7phj-vgxq-r67h: Microsoft Security Advisory CVE-2026-114157 - ASP.NET Core Security Feature Bypass Vulnerability

Executive summary

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

A Kestrel named-pipe listener configured with CurrentUserOnly can lose protected namespace ownership during recovery, allowing another local user to claim the pipe path.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/507

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 (base score) - Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C - Weakness: CWE-362 - MSRC severity: Important - Impact: Security Feature Bypass

Affected Platforms

- Platforms: Windows - Architectures: Arm64, x64, x86

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

Microsoft.AspNetCore.Server.Kestrel.Transport.NamedPipes ships in the ASP.NET Core shared framework and runtime packs; it is not a separately packable NuGet package.

Affected intervals and patched release versions are listed below.

.NET 8.0 - affected runtime packages

Package | Affected version | Patched version --- | --- | --- 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.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.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.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

The .NET 11.0.0 release is fixed; affected prereleases are listed above.

Advisory FAQ

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

Review Windows applications that use Kestrel's Named Pipes transport and identify their deployed ASP.NET Core versions. Compare deployed versions with the affected intervals above. Self-contained applications include their own framework; updating a machine-wide installation does not replace their embedded copies.

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

Install the applicable ASP.NET Core runtime update and restart applications. Rebuild and redeploy affected self-contained applications with fixed runtime packs. An SDK update alone does not replace runtime or framework files already embedded in deployed applications. Use the patched version listed for the affected servicing line.

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-2026-114157

Acknowledgements

- Antonio Alonso-Stepanov

Revisions

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