GHSA-f7vh-h5g3-7jrh: High severity nuget/aspire.hosting vulnerability

Executive summary

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

Disclosure of an Aspire Dashboard authentication cookie to a linked service can allow an attacker-controlled container to replay the authenticated session and execute code as the host developer.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/503

CVSS Details

- Version: 3.1 - Severity: High - Score: 7.5 - Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H - Weakness: CWE-201 (Insertion of Sensitive Information Into Sent Data)

Affected Platforms

- Platforms: macOS - Architectures: x64, Arm64

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

Standalone Aspire

Package | Affected version | Patched version --- | --- | --- Aspire.Hosting.AppHost | < 13.6.5 | 13.6.5 Aspire.Hosting | < 13.6.5 | 13.6.5

The affected scenario involves a Dashboard-authenticated AppHost workflow with an attacker-controlled container and a linked HTTPS YARP gateway. The affected hosting code is in Aspire.Hosting, a dependency of Aspire.Hosting.AppHost. Aspire.AppHost.Sdk supplies the AppHost package implicitly unless the project overrides the default references.

Advisory FAQ

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

The reported scenario involves a developer starting an Aspire AppHost, authenticating to its Dashboard, and following a resource link that routes to an attacker-controlled container. All released versions through 13.6.4 are affected.

Aspire ships independently of .NET. Installing a .NET runtime or SDK update does not establish that the affected Aspire components have been updated.

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

Update the AppHost project's Aspire.Hosting.AppHost package reference to version 13.6.5 or later. If the project obtains this package implicitly through Aspire.AppHost.Sdk, update that SDK reference to version 13.6.5 or later. Explicit package references or central version pins must also resolve Aspire.Hosting to version 13.6.5 or later. Restore dependencies, rebuild, and restart the AppHost after updating.

Updating only the .NET runtime, .NET SDK, Aspire CLI, or standalone Dashboard does not replace the AppHost project's hosting dependencies.

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 in the Aspire repository.

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-2026-120006

Acknowledgements

- samthewhitehat

Revisions

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