KB5075971 is the ESU Monthly Rollup Update for Windows Server 2012. It was released on 10 February 2026 under the ‘Patch Tuesday’ program.
Salient points
- KB5075971 supersedes KB5073698 released in January 2026.
- KB5075971 requires the KB5071813 Servicing Stack Update to be installed prior to installing the main monthly rollup update.
- Without the installation of KB5071813, the ESU KB5075971 cannot be installed. For WSUS administrators, KB5071813 needs to be approved before KB5075971 will be fetched and deployed automatically.
- If you install language pack after installing KB5075971, you would need to reinstall the security update. All language pack installations must be completed before installing the monthly rollup update on Windows Server 2012.
- KB5075971 is an Extended Security Update. A valid subscription key to the ESU program is required before installing the monthly rollup update.
- Windows Server 2012 is impacted by 13 security vulnerabilities reported in Feb 2026 security bulletin.
- Five zero-day vulnerabilities have been disclosed for Windows Server 2012 and Windows Server 2012 Server Core installation in February security bulletin.
- The latest cumulative update for Internet Explorer 11 on Windows Server 2012 continues to be KB5066840 released in October 2025. So, new update for Internet Explorer is not needed in February 2026.
Servicing Stack Update KB5071813
The Servicing Stack Update for Windows Server 2012 for Feb 2026 is KB5071813. It corresponds to KB5075971 and KB5073698 ESU.
For automated deployments of KB5073698 through the Windows Update program, the Servicing Stack Update KB5071813 is offered for installation as part of the installation process of the monthly rollup update KB5073698.
The Servicing Stack Update file is a small file around 10 MB size Upon installation, it would not cause server reboot.
Once the SSU is installed, you can proceed with the installation of the main monthly rollup update KB5075971.
Download KB5075971
You can download the monthly rollup update KB5075971 for Windows Server 2012 from the Windows Update Catalog page shared below:
We would reiterate that you need a valid ESU program subscription before you could install the ESU KB5075971 on Windows Server 2012.
Zero-day Vulnerabilities
Five new zero-day security vulnerability has been reported for Windows Server 2012 and Windows Server 2012 Server Core installation in February month’s security bulletin released by Microsoft on 10 Feb 2026.
| CVE Details | CVSS Score | Comments |
|---|---|---|
| CVE-2026-21510 | 8.8 | Security Feature Bypass Vulnerability in Windows Shell |
| CVE-2026-21513 | 8.8 | Security Feature Bypass Vulnerability in MSHTML Framework |
| CVE-2026-21519 | 7.8 | Elevation of Privilege Vulnerability in Desktop Window Manager |
| CVE-2026-21525 | 6.2 | Denial of Service Vulnerability in Windows Remote Access Connection Manager |
| CVE-2026-21533 | 7.8 | Elevation of Privilege Vulnerability in Windows Remote Desktop Services |
Internet Explorer Cumulative Update – KB5066840
To secure the Windows Server 2012, you also need to patch Internet Explorer 11 with the latest cumulative update. KB5066840 is the cumulative update for Internet Explorer released on 14 October 2025. No new security update for Internet Explorer 11 was released in November 2025.
You can download the IE Cumulative Update for Windows Server 2012 from the link shared below:
Download Cumulative Update for Internet Explorer – KB5066840 (54.9 MB)
KB5075971 – Changelog
Since this is an ESU, the focus remains on securing the Windows Server 2012 deployments. The following changes have been reported for KB5075971:
- [Internal Windows OS] Miscellaneous security improvements were made to internal Windows OS functionality.
Simplifying technology, one step at a time.