KB5077179

Microsoft has released cumulative security update KB5077179 (build 28000.1575) for Windows 11 version 26H1 as part of the February 2026 Patch Tuesday. This update is specifically intended for PCs based on Arm processors, including new devices with Snapdragon X2 Elite, X2 Elite Extreme, and X2 Plus chips that are not yet on sale. Build 28000.1575 is automatically installed on such devices only if you have opted out of testing in the Canary Channel with build 28000.1340 and have not yet updated to build 28020.1362 (Canary) or newer.

• Graphics. Fixed an issue where on some graphics card configurations a system crash occurred related to dxgmms2.sys, leading to a KERNEL_SECURITY_CHECK_FAILURE error.
• .NET Framework 3.5. Starting with Windows 11 version 26H1, .NET Framework 3.5 is no longer available as a Windows feature on demand. A separate standalone installer is now required for installation. More info: go.microsoft.com/fwlink/?linkid=2348700.
• Network. Addressed an issue where some devices could not connect to certain Wi-Fi networks protected with WPA3-Personal.
• BitLocker. Fixed a bug where necessary tests were missing from BitLocker Hardware Lab Kit (HLK) test sets as part of the Windows Hardware Certification Program. These tests now display correctly.
• System stability. Resolved a critical issue where the TrustedInstaller service could become unresponsive and in some cases block Windows startup.

Microsoft will release Windows 11 version 26H1 in spring 2026 exclusively for new Arm PCs based on Snapdragon X2. This update is built on the new Bromine platform and includes internal performance and stability improvements for the new Qualcomm processors. Installation via Windows Update: open Settings > Windows Update and click Check for updates. A system restart is required to complete installation.

How the new features work:

Graphics: Fixed a crash in dxgmgs.sys occurring on some GPU configurations. The system mishandled the direct memory access (DMA) graph between the GPU and graphics kernel manager, leading to kernel integrity violation and KERNEL_SECURITY_CHECK_FAILURE due to an invalid command ring buffer state.

.NET Framework 3.5: Starting with Windows 11 26H1, this component is removed from the Features on Demand (FoD) list. Windows images no longer contain the Microsoft-Windows-NetFx3 provisioning package in the component store. The installer now downloads and installs dependencies separately, requiring an external MSI file with signed and verified CLR 2.0 assemblies.

Network: Fixed a bug in the supplicant stack for WPA3‑Personal – PTK (Pairwise Transient Key) was incorrectly computed during SAE handshake. The rsn_supplicant mechanism sometimes terminated the negotiation with an authentication code without waiting for AP confirmation, causing endless connection attempts. Validation of the BSS parameter extract is now fixed.

BitLocker: Hardware Lab Kit test sets lacked checks for logical vulnerabilities in TPM metadata rollback. Scripts emulating sudden power‑loss attacks during the volume encryption phase have been added. This allows certifying devices for correct BitLocker policy recovery when the system partition header is corrupted.

System stability: TrustedInstaller became unresponsive due to a deadlock in Windows Update package servicing transactions. The service acquired a mutex on the C:\Windows\WinSxS folder and did not release it when catalog file signature verification failed. Timeout logic is fixed – the service now forcibly terminates hung operations after 60 seconds.

The last 10 Windows updates: