Microsoft has rolled out its January 2026 Patch Tuesday updates, with KB5074109 being the cumulative update for Windows 11 versions 25H2 and 24H2, and KB5073455 for version 23H2. These mandatory updates, released on January 13, 2026, aim to enhance system security and stability across Windows 11 devices. The Patch Tuesday release addresses a total of 114 vulnerabilities, including 8 critical ones and notably, one actively exploited zero-day vulnerability in Desktop Window Manager (CVE-2026-20805), and two other publicly disclosed vulnerabilities. Beyond security, the update brings several key bug fixes. It resolves an issue causing 'No route to host' errors in Windows Subsystem for Linux (WSL) mirrored networking, especially when accessing corporate resources over VPNs. Azure Virtual Desktop (AVD) environments will see fixes for RemoteApp connection failures. Additionally, a power performance bug on devices equipped with a Neural Processing Unit (NPU) that caused them to stay powered on when idle has been fixed. The update also includes changes like the removal of certain legacy modem drivers and new Secure Boot certificates. Users can obtain these updates through Windows Update or by downloading the direct .msu installer files from the Microsoft Update Catalog. While 25H2 isn't a major feature release, it's a critical security and maintenance update, building upon the Windows 11 2025 Update which was generally available on September 30, 2025.