Microsoft has addressed a critical bug caused by recent Windows updates that disrupted HTTP/2 localhost connections and IIS websites on Windows 11 and Windows Server 2025. The fix includes automatic rollback for most users and a targeted solution for enterprise-managed devices, with a permanent update expected soon. #HTTP2 #IIS #WindowsUpdate #KB5066835
Keypoints
- The bug was triggered by the KB5066835 update and caused connection reset errors on localhost.
- It affected applications like Visual Studio debugging, SSMS Entra ID, and Duo Desktop app.
- Microsoft confirmed the issue and linked it to a bug in HTTP.sys for ASP.NET Core.
- Users were advised to manually check for updates and restart their devices to fix the problem.
- Future Windows updates will include a permanent fix for this connection disruption.