Microsoft Windows 11 23H2 Update Version OS Build 22631.6491

KB5073455 for Windows 11 version 23H2 (OS Build 22631.6491) delivers January 2026 security fixes, quality improvements, and non-security updates from KB5071417. It also includes Secure Boot certificate targeting changes and a security hardening update for credential autofill.

• Addresses security issues in Windows OS.
• Introduces a security hardening behavior that restricts certain applications from autofilling credentials during remote support sessions or automated authentication workflows.
• Updates WinSqlite3.dll; some security software previously flagged it as vulnerable.
• Adds Secure Boot device-targeting data to support phased deployment of new Secure Boot certificates.

• Fixes an issue where Remote Desktop Protocol (RDP) connections could fail and require a device restart.
• Fixes an issue where apps such as Outlook, Teams, Edge, Chrome, and Excel might close unexpectedly when entering text.
• Removes modem drivers agrsm64.sys, agrsm.sys, smserl64.sys, and smserial.sys; hardware dependent on them will no longer work.
• Includes servicing stack quality improvements in KB5071963.

• Adds Secure Boot certificate targeting data to Windows quality updates for phased certificate deployment.

• Some devices with Secure Launch may fail to shut down or hibernate and restart instead.
• Some devices with Virtual Secure Mode enabled might fail to shut down or hibernate.
• Apps may become unresponsive or error when opening or saving files to cloud-based storage such as OneDrive or Dropbox.
• Azure Virtual Desktop and Windows 365 sign-in failures occurred with the Windows App on some Windows builds.

• Use EKB KB5027397 to update to Windows 11, version 23H2.
• Windows Update does not include Microsoft Store app updates.
• Secure Boot certificates used by most Windows devices are set to expire starting in June 2026.
• The update includes fixes and quality improvements from KB5071417.

Product Information

Vendor: Microsoft

Product: Windows 11

Product type: Software

Application category: Utilities

Platform: Windows

Variant: 23H2

Version: OS Build 22631.6491

Vendor information published: Jan 13, 2026

Original release notes: View on vendor site

Published on updatealert.io: Jun 3, 2026

Description: Client operating system for modern desktop and enterprise environments.