Windows Server · 2025 · Release · Security update (Patch Tuesday)

January 13, 2026—KB5073379 (OS Build 26100.32230)

Windows Server 2025: Current LTSC release

All 2025 builds JSON — this build from the builds API

Microsoft's known issues — KB5073379

  • Issue Known issue After installing KB5070881 or later updates, Windows Server Update Services (WSUS) does not display synchronization error details within its error reporting. This functionality is temporarily removed to address the Remote Code Execution Vulnerability, CVE-2025-59287 . After installing the January 2026 security update ( KB5073379 ), released on January 13, 2026, credential prompt failures occurred during Remote Desktop connections using the Windows App on Windows client devices, impacting Azure Virtual Desktop and Windows 365. The issue affects Windows App on specific Windows builds, causing sign-in failures. After installing this update, some applications may become unresponsive or encounter Workaround: This issue is addressed in KB5077793 . If you are experiencing this issue, please contact the application developer for possible alternative methods of accessing the files. For Outlook-specific scenarios, moving the PST files out of OneDrive should resolve the issue. For guidance, please see documentation at How to remove an Outlook .pst data file from OneDrive . In addition, email accounts can still be accessed via webmail, if supported by your email provider. We are actively working on a resolution and will share an update as soon as more information becomes available.

Microsoft's release notes for KB5073379 ›

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