Elevation of Privilege Vulnerability in.NET ASP.NET Core
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 parsing.
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. This vulnerability appears to be due to improper parsing within the handler, potentially allowing unauthorized privilege escalation. The affected component is Microsoft.AspNetCore.Authentication.Negotiate (nuget) for versions >=10.0.0, <=10.0.9 || >=9.0.0, <=9.0.17 || >=8.0.0, <=8.0.17.
Professional software engineers using these.NET versions in their projects are advised to assess their exposure. The recommended action, as per the internal classification, is to upgrade to the patched versions: 10.0.10 for.NET 10, 9.0.18 for.NET 9, and 8.0.18 for.NET 8.
For more detailed information, consult the primary sources. The severity of this threat is high, and further details are expected as the investigation progresses.
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.