Microsoft has initiated the year 2026 with the release of its first set of security updates for the Windows operating system and various Microsoft products. The January Patch Tuesday has addressed over 110 security vulnerabilities, encompassing a broad spectrum of platforms including Windows, Microsoft Office, Edge, Azure components, and additional services.
The updates are accessible for all supported versions of Windows. Notably, Windows 10 is receiving security fixes exclusively through the Extended Security Updates (ESU) program, while Windows 11 versions 24H2 and 25H2 are the primary consumer releases benefiting from these updates.
Microsoft Security Updates — January 2026
Executive Summary:
- Microsoft has released approximately 112–114 security updates in total.
- Around 8 vulnerabilities have been rated Critical.
- At least one zero-day vulnerability is actively exploited, as confirmed by Microsoft.
- Security fixes encompass Windows, Office, Edge, Azure, and server components.
Windows clients with known issues
- Windows 11: versions 23H2, 24H2, 25H2
Windows Server products with known issues
- Windows Server 2023
- Windows Server 2025
Product Overview
A detailed examination of affected Windows versions reveals the following vulnerability counts:
Windows 11:
Windows 11 version 24H2
- Numerous vulnerabilities have been addressed.
- Includes flaws related to remote code execution, privilege escalation, spoofing, and information disclosure.
Windows 11 version 25H2
- Shares the same vulnerability scope as 24H2.
- No critical vulnerabilities specific to this release.
Windows 11 version 23H2 (Enterprise & Education)
- Continues to receive support through enterprise servicing channels.
- Only cumulative security updates are provided.
Windows 10
Windows 10 (Extended Security Updates only)
- Applicable solely to systems enrolled in ESU.
- No feature updates are included.
- General support concluded in October 2025.
Windows Server
- Windows Server 2016
- Windows Server 2019
- Windows Server 2022
- Windows Server 2023
- Windows Server 2025
All supported server versions have received the January security updates. While no critical vulnerabilities were publicly disclosed for server products, several important vulnerabilities have been addressed.
Windows Security Updates
Windows 11 version 24H2 and 25H2
Support page: KB5074109
Updates and improvements:
- Security fixes for multiple remote code execution and elevation of privilege vulnerabilities.
- Improvements to system stability and reliability.
- Changes related to Secure Boot and virtualization-based security.
Windows 11 version 23H2 (Enterprise & Education)
Support page: KB5073455
Updates and improvements:
- Security fixes and quality enhancements.
- Includes changes related to Secure Boot certificates.
Known issue:
- Systems with Secure Launch enabled may experience shutdown or sleep mode failures.
- Devices may restart instead.
Workaround:
Utilize a command prompt and execute:
shutdown /s /t 0
Currently, Microsoft has no workaround for sleep mode issues.
Windows 10 (ESU)
Support page: KB5073724
- Security-only update.
- Available exclusively to ESU-enrolled systems.
- Removes outdated modem drivers as part of the servicing process.
Windows Server Updates
- Windows Server 2025: KB5073379
- Windows Server 2023: KB5073450
These updates are security-focused, with no feature changes introduced.
Servicing Stack and Quality Updates
- KB5077800 — Servicing Stack Update (released January 17, 2026)
- Enhances update installation reliability for older Windows builds.
Microsoft Office Security Updates
On January 13, 2026, Microsoft also rolled out security updates for Office and server components.
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 have also received corresponding updates.
Known Issues After Installing January Updates
Remote Desktop / Azure Virtual Desktop / Windows 365
Post-installation of the January updates, some users have reported:
- Credential prompt failures.
- Authentication issues in Azure Virtual Desktop and Windows 365.
- Problems primarily affect the new Windows App.
Workarounds:
- Utilize the classic Remote Desktop client.
- Employ the web-based RDP client.
Microsoft is aware of the issue and is actively investigating.
Windows 11 23H2 Shutdown and Sleep Issues
- Impacts devices with Secure Launch enabled.
- Disrupts normal shutdown and sleep functionality.
- Documented in Windows Release Health.
As of January 18, 2026, Microsoft has released out-of-band fixes for certain affected systems.
How to Install the January 2026 Updates Immediately
While security updates are generally rolled out automatically, manual installation remains an option:
- Open the Start menu.
- Type Windows Update and open it.
- Select Check for updates.
- Choose Download & install all.
Recommendation:
It is advisable to create a full system backup before proceeding with updates, particularly on production systems.
Direct Update Downloads
Windows 11
- KB5074109 — Cumulative Update for Windows 11 24H2 / 25H2
- KB5073455 — Windows 11 23H2 (Enterprise & Education)
Windows 10 (ESU)
- KB5073724 — January 2026 ESU update
