Windows 11 Kb5074109 & Kb5073455 Cumulative Updates Released (2026)

Microsoft has released Windows 11 KB5074109 and KB5073455  cumulative updates for versions 25H2/24H2 and 23H2 to fix security vulnerabilities, bugs, and add new features.

Today's updates are mandatory as they contain the January 2026 Patch Tuesday security patches for vulnerabilities discovered in previous months.

You can install today's update by going to Start > Settings > Windows Update and clicking on 'Check for Updates.'

You can also manually download and install the update from the Microsoft Update Catalog.

This is the third 'Patch Tuesday' release for version 25H2, but as it's based on version 24H2, there are no exclusive or special changes. You'll get the same fixes across the two versions of Windows 11.

After installing today's security updates, Windows 11 25H2 (KB5074109) will have its build number changed to Build 26200.7623 (or 26100.7462  in case of 24H2), and 23H2 (KB5073455) will be changed to 226x1.6050.

This update mostly contains bug fixes, and here's everything you need to know:

[Compatibility] This update removes the following modem drivers: agrsm64.sys (x64), agrsm.sys (x86), smserl64.sys (x64) and smserial.sys (x86). Modem hardware dependent on these specific drivers will no longer work in Windows.

Fixed: This update addresses an issue where mirrored networking in Windows Subsystem for Linux (WSL) could fail causing “No route to host” errors and preventing access to corporate resources over VPN connections, even when the Windows host remained connected. This might occur after installing KB5067036.

Fixed: This update addresses an issue where you might experience RemoteApp connection failures in Azure Virtual Desktop (AVD) environments. This might occur after installing KB5070311.

Source: BleepingComputer