Windows 11 Receives Emergency Patch KB5129195
On September 16, Microsoft rolled out an urgent update, KB5129195, for Windows 11 versions 24H2 and 25H2. This patch updates the build numbers to 26100.9457 and 26200.9457 respectively. It addresses a severe security flaw, CVE-2026-62721, found in the Windows User-Mode Power Service that allowed attackers to elevate privileges to SYSTEM level by exploiting power request manipulations. Alongside this critical fix, the update resolves several other system issues.
Key Fixes Included in the Patch
The update tackles several major problems, including crashes in the Remote Desktop service that caused RDP sessions to disconnect after a few minutes. It also fixes freezes affecting the management console and File Explorer. Additionally, it restores folder sharing functionality with Linux virtual machines using the Plan9 protocol in Hyper-V. Audio issues have been addressed as well, with sound returning to multi-channel USB Audio Class 1.0 devices.
Despite these improvements, some challenges remain unresolved. The “Code 10” error causing volume lock issues on certain USB sound cards persists. Some AMD graphics drivers continue to crash, and File History backup services still require further attention.
Installation of KB5129195 typically takes about ten minutes and usually necessitates one system reboot. The update is automatically distributed via Windows Update, while enterprise administrators can manually download it from the Microsoft Update Catalog or deploy it through Intune and WSUS. This release follows a previous update that patched over 970 vulnerabilities across Microsoft products, including two actively exploited zero-day flaws.
This release highlights Microsoft’s ongoing commitment to enhancing product security amid rising cyber threats. While critical vulnerabilities have been addressed, remaining issues show that efforts to improve Windows 11’s stability and safety are still underway. Windows 11 users are strongly advised to install this update promptly to maintain optimal protection and system performance.