January 13, 2026—KB5073379 (OS Build 26100.32230)
Applies To
Release Date:
13/01/2026
Version:
OS Build 26100.32230
​​​​​This cumulative update for Windows Server 2025 (KB5073379), includes the latest security fixes and improvements, along with non-security updates from last month’s optional preview release. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates.
To view the latest updates about this release, visit the Windows release health dashboard or the update history page for Windows Server 2025. Â
Announcements and messages
This section provides key notifications related to this release, including announcements, change logs, and end-of-support notices.
Starting with the January 2026 security update, Windows Server 2025 will have its own KB identifiers and build numbers. These identifiers are separate from those for Windows 11 versions 24H2 and 25H2. This change improves clarity for administrators. Installation and management processes remain the same.
Windows Secure Boot certificate expiration
Important: Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. This might affect the ability of certain personal and business devices to boot securely if not updated in time. To avoid disruption, we recommend reviewing the guidance and taking action to update certificates in advance. For details and preparation steps, see Windows Secure Boot certificate expiration and CA updates.
Improvements
This security update contains fixes and quality improvements from KB5072033 (released December 9, 2025). The following summary outlines key issues addressed by this update. Also, included are available new features. The bold text within the brackets indicates the item or area of the change. ​​​​
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[Compatibility]Â 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.
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[Networking (known issue)] Fixed: This update addresses an issue where you might experience RemoteApp connection failures in Azure Virtual Desktop (AVD) environments. This might occur after installing KB5072033.
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[Servicing (known issue] This update addresses an issue where devices that installed the out-of-band update (KB5070881) stopped receiving Hotpatch updates. Affected machines will resume Hotpatch updates after installing the January 2026 baseline update.
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[Secure Boot]Â Starting with this update, Windows quality updates include a subset of high confidence device targeting data that identifies devices eligible to automatically receive new Secure Boot certificates. Devices will receive the new certificates only after demonstrating sufficient successful update signals, ensuring a safe and phased deployment.
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[Windows Deployment Services (WDS] This update introduces a change in behavior in which WDS will stop supporting hands-free deployment functionality by default. Detailed guidance for IT administrators is available in Windows Deployment Services (WDS) Hands‑Free Deployment Hardening Guidance.Â
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[WinSqlite3.dll] Fixed: The Windows core component, WinSqlite3.dll, has been updated. Previously, some security software might have detected this component as vulnerable.Â
Note:Â WinSqlite3.dll is a separate component from sqlite3.dll, which is found in application-specific directories and is not a Windows component. If security applications continue to detect sqlite3.dll as vulnerable, contact the developer of the app using sqlite3.dll for an update. If sqlite3.dll is being used by a Microsoft app, install the latest version of the app from the Microsoft Store.
If you've already installed previous updates, your device will download and install only the new updates included in this package.
For more information about security vulnerabilities, please refer to the Security Update Guide and the January 2026 Security Updates.
Windows Server 2025 servicing stack update (KB5072725) -26100.32131
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates. To learn more about SSUs, see Simplifying on-premises deployment of servicing stack updates.
Known issues in this update
After installing KB5070881Â 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.Â
How to get this update
Before you install this update
​​​​​​​Microsoft now combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
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This update downloads and installs automatically from Windows Update and Microsoft Update. |
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Next Step |
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This update downloads and installs automatically from Windows Update for Business in accordance with configured policies. |
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Yes 1 |
Before you install this update To get the standalone package(s) for this update, go to the Microsoft Update Catalog website. This KB contains one or more MSU files that require installation in a specific order. Install this update Method 1: Install all MSU files together Download all MSU files for KB5073379 from Microsoft Update Catalog and place them in the same folder (for example, C:/Packages). Use Deployment Image Servicing and Management (DISM.exe) to install the target update. DISM will use the folder specified in PackagePath to discover and install one or more prerequisite MSU files as needed. Updating Windows PC To apply this update to a running Windows PC, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
Or use Windows Update Standalone Installer to install the target update. Updating Windows Installation media To apply this update to Windows Installation media, see Update Windows installation media with Dynamic Update. Note: When downloading other Dynamic Update packages, ensure they match the same month as this KB. If the SafeOS Dynamic Update or Setup Dynamic Update is not available for the same month as this KB, use the most recently published version of each. To add this update to a mounted image, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
​​​​​​​​​​​​​​ Method 2: Install each MSU file individually, in order Download and install each MSU file individually either using DISM or Windows Update Standalone Installer in the following order:
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1 This latest cumulative update includes updates for AI components. Even though the AI component updates are included in the update, the AI components are only applicable to Windows Copilot+ PCs and will not install on Windows PC or Windows Server.
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Available |
Next Step |
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This update will automatically sync with Windows Server Update Services (WSUS) if you configure Products and Classifications as follows: Product: Microsoft Server operating system-24H2 Classification: Security Updates |
If you want to remove the LCU
To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.
Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.
File Information
For a list of the files provided in this update, download the file information for cumulative update 5073379.Â
For a list of the files provided in the servicing stack update, download the file information for the SSU (KB5072725) - version 26100.32131.Â
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