From Mashable · Matt Binder · · 1m 30s
Microsoft ships an emergency patch for its own Patch Tuesday
A record September update fixed 966 flaws and broke remote desktop, USB audio and Linux VMs. Here's what the fix covers.
In brief
A record September update fixed 966 flaws and broke remote desktop, USB audio and Linux VMs. Here's what the fix covers. Install KB5129194 on Windows 11 26H1 now. It keeps last week's zero-day protections and fixes most of what that update broke, though some older USB audio devices may still fail. Originally reported…
A record Patch Tuesday
Microsoft's September 8 update fixed 966 flaws across its products, the most ever. Two of them were zero-days that attackers were already using.
Then a patch for the patch
Six days later, on September 14, Microsoft pushed out an emergency update outside its usual schedule. KB5129194 targets Windows 11 version 26H1.
“Microsoft rolled out an emergency, out-of-band patch for the patch.”
What the update broke
Users said Remote Desktop Services got unstable and some USB audio devices stopped working. Apps that run Linux VMs on Hyper-V, like Claude Cowork, also had problems.
Audio is only partly fixed
The new patch fixes multichannel audio failures, but some USB Audio Class 1.0 devices may still fail to start or play sound. Microsoft says it is working on a fix.
Two zero-days, full system control
CVE-2026-81963 hit the Windows Update Stack and CVE-2026-85880 hit ALPC. Both gave attackers System privileges, and Microsoft hasn't said how they were used.
Update now anyway
Install the latest update for your Windows 11 version as soon as you can. You get last week's security fixes plus repairs for most of what they broke.
The main idea
Install KB5129194 on Windows 11 26H1 now. It keeps last week's zero-day protections and fixes most of what that update broke, though some older USB audio devices may still fail.
