Elevation of Privilege Vulnerability in.NET Core Authentication Handler
An elevation of privilege vulnerability reportedly exists in the ASP.NET Core Negotiate authentication handler in .NET 8,.NET 9, and.NET 10 due to improper validation. This affects any Microsoft.NET project using the affected package versions.
What happened
An elevation of privilege vulnerability is under investigation in the ASP.NET Core Negotiate authentication handler for.NET 8,.NET 9, and.NET 10. The vulnerability appears to be due to improper validation within the authentication handler. This could potentially allow an attacker to gain elevated privileges within affected systems.
The vulnerability affects the Microsoft.AspNetCore.Authentication.Negotiate NuGet package versions >=10.0.0,<=10.0.9, >=9.0.0,<=9.0.17, and >=8.0.0,<=8.0.17. Any.NET project utilizing these package versions may be at risk.
To assess your exposure, check your project dependencies for the affected NuGet package versions. If your project is using any of the vulnerable versions, it is recommended to upgrade to the patched versions: 10.0.10 for.NET 10, 9.0.18 for.NET 9, and the appropriate version for.NET 8. For more detailed information, consult the primary sources.
How 0Day mitigates this
Microsoft.AspNetCore.Authentication.Negotiate is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.