Microsoft has released the first security update of 2026 for its Windows operating system and other Microsoft products. January Patch Tuesday addresses more than 110 security vulnerabilities in Windows, Microsoft Office, Edge, Azure components, and additional services.
Updates are available for all supported Windows versions. Windows 10 continues to receive security fixes only under Microsoft’s Extended Security Updates (ESU) program, while Windows 11 versions 24H2 and 25H2 are the primary consumer releases to receive updates.
Our monthly Patch Day overview provides home users and system administrators with a concise summary of released updates, vulnerability severity, known issues, and direct download resources.
Microsoft Security Update – January 2026
executive Summary:
- Microsoft released About 112-114 security updates overall
- About 8 weaknesses are rated Serious
- At least one zero-day vulnerability is actively exploitedConfirmed by Microsoft
- fix safety cover Windows, Office, Edge, Azure, and Server components
Windows clients with known issues
- Windows 11: Edition 23H2, 24h2, 25H2
Windows Server products with known issues
- windows server 2023
- windows server 2025
Product Overview
Below are details of the affected Windows versions and reported vulnerability counts.
Windows 11:
windows 11 version 24h2
- Dozens of vulnerabilities were fixed
- This includes remote code execution, privilege escalation, spoofing, and information disclosure flaws.
windows 11 version 25h2
- Same range of vulnerabilities as 24H2
- No critical vulnerabilities specific to this release only
Windows 11 Version 23H2 (Enterprise & Education)
- Still supported through enterprise servicing channels
- Receives only cumulative security updates
windows 10
Windows 10 (Extended Security Updates only)
- Applies only to systems enrolled in ESU
- no feature updates
- General support ends in October 2025
windows server
- windows server 2016
- windows server 2019
- windows server 2022
- windows server 2023
- windows server 2025
All supported server versions received January security updates. No critical vulnerabilities for server products were publicly disclosed, but several critical vulnerabilities were resolved.
windows security update
Windows 11 version 24H2 and 25H2
Updates and Improvements:
- Security solutions for multiple remote code execution and elevation of privilege vulnerabilities
- Improve system stability and reliability
- Servicing changes related to Secure Boot and virtualization-based security
Windows 11 Version 23H2 (Enterprise & Education)
Updates and Improvements:
- Safety improvements and quality improvements
- Contains changes related to Secure Boot certificates
known issue:
- Systems with Secure Launch enabled may fail to shut down or enter sleep mode
- Devices may restart instead
Solution:
Use command prompt and run:
shutdown /s /t 0
Microsoft does not have a solution for sleep mode at this time.
windows 10 (esu)
- Security Updates Only
- Available exclusively for ESU-designated systems
- Removes old modem drivers as part of servicing
windows server update
- Windows Server 2025: KB5073379
- Windows Server 2023: KB5073450
Security update only, no feature changes.
Servicing Stack and Quality Updates
- KB5077800 – Servicing Stack Update (released January 17, 2026)
- Improves update installation reliability for older Windows builds
Microsoft Office Security Update
Microsoft released Office and server component security updates on January 13, 2026.
Office updates include:
- Excel 2016 – KB5002831
- Office 2016 – KB5002826
- Word 2016 – KB5002829
Sharepoint Server:
- SharePoint Server Subscription Edition – KB5002822
- SharePoint Server 2019 – KB5002825
- SharePoint Server 2016 – KB5002828
Language packs received relevant updates.
Known issues after installing the January Update
Remote Desktop/Azure Virtual Desktop/Windows 365
After installing the January update, some users report:
- Credential prompt failures
- Authentication issues in Azure Virtual Desktop and Windows 365
- Issues primarily affect new Windows apps
Solution:
- Use the Classic Remote Desktop Client
- Use a web-based RDP client
Microsoft has acknowledged the issue and is actively investigating.
Windows 11 23H2 Shutdown and Sleep Problems
- Affects Secure Launch enabled devices
- Prevents normal shutdown and sleep behavior
- Documented in Windows Release Health
Microsoft has released out-of-band fix By January 18, 2026 for some affected systems.
How to install the January 2026 update immediately
Security updates are released automatically, but manual installation is possible.
- open start menu
- Type Windows Update and open it
- choose check for updates
- choose Download and Install All
Recommendation:
Create a full system backup before installing updates, especially on production systems.
direct update download
windows 11
- KB5074109 — Cumulative Update for Windows 11 24H2/25H2
- KB5073455 — Windows 11 23H2 (Enterprise & Education)
windows 10 (esu)
- KB5073724 — January 2026 ESU Update
additional resources
