Microsoft released emergency out-of-band updates on September 14 to address critical compatibility issues introduced by the September security patch. The updates target multiple versions of Windows 11 and Windows 10, bringing them to new build numbers.
For Windows 11 26H1, the update KB5129194 raises the build to 28000.2956. Windows 11 25H2 and 24H2 receive KB5129195, reaching builds 26200.9457 and 26100.9457 respectively. Windows 10 22H2 and 21H2 are updated via KB5129236 to builds 19045.7727 and 19044.7727.
The patches resolve Remote Desktop Services (RDS) instability, including connection failures and server unresponsiveness. Other fixes address issues with Hyper-V Linux virtual machine folder sharing via Plan9 and malfunctions in USB Audio Class 1.0 devices when using multi-channel modes.
Additionally, the updates include security patches for two privilege escalation vulnerabilities. These involve CVE-2026-62721, affecting the Windows User Mode Power Service, and CVE-2026-85921, related to the Windows security kernel mode.
