KB5075970 is the ESU Monthly Rollup Update for Windows Server 2012 R2. It was released on 11 February 2026 under the ‘Patch Tuesday’ program.
Salient points
- KB5075970 supersedes KB5073696 released in January 2026.
- KB5075970 requires a Servicing Stack Update to be installed prior to installing the main monthly rollup update. KB5068783 is the SSU corresponding to KB5075970. This SSU was released in November 2025. If you applied the November security update or December security update on Windows Server 2012 R2, the SSU or Servicing Stack Update would be already there on the server.
- If you install language pack after installing KB5075970, you would need to reinstall the security update once again. All language pack installations must be completed before installing the monthly rollup update on Windows Server 2012 R2.
- KB5075970 is an Extended Security Update. A valid subscription key to the ESU program is required before installing the monthly rollup update.
- Windows Server 2012 R2 is impacted by 15 security vulnerabilities reported in February 2026 security bulletin.
- Five zero-day vulnerabilities affect Windows Server 2012 R2 and Windows Server 2012 R2 Server Core installation.
- KB5075970 corresponds to build 6.3.9600.23022 for Windows Server 2012 R2.
- Meanwhile, the last cumulative update for Internet Explorer on Windows Server 2012 R2 was last released in October 2025 (KB5066840)
Servicing Stack Update KB5068783
The Servicing Stack Update for Windows Server 2012 R2 for November, December, January and February is KB5058783. It corresponds to KB5068905 ESU, KB5071503, KB5073696 ESU and KB5075970 ESU.
For automated deployments of KB5075970 through the Windows Update program, the Servicing Stack Update KB5068783 is offered for installation as part of the installation process of the monthly rollup update KB5075970. No further action is needed to install KB5068783 for automated installations of KB5075970.
WSUS administrators need to authorize or approve KB5068783 before KB5075970 is fetched and installed in WSUS.
If you choose to deploy KB5075970 manually, you need to download and install KB5068783 on the Windows Server 2012 R2.
The Servicing Stack Update file is a small file of 10.6 MB. 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 KB5075970.
Download KB5075970
You can download the monthly rollup update KB5075970 for Windows Server 2012 R2 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 KB5075970 on Windows Server 2012 R2.
Zero-day Vulnerabilities
Five zero-day vulnerability affects Windows Server 2012 R2 and Windows Server 2012 R2 Server Core installation, as per the latest security reported released by Microsoft.
The zero-day vulnerabilities are shared below:
| 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 |
Critical vulnerabilities
No Critical vulnerabilities have been reported for Windows Server 2012 R2 in February 2026.
KB5071503 – Changelog
Since this is an ESU, the focus remains on securing the Windows Server 2012 R2 deployments. The following changes have been reported for KB5071503:
- [Internal Windows OS] Miscellaneous security improvements were made to internal Windows OS functionality.
Internet Explorer Cumulative Update – KB5066840
To secure the Windows Server 2012 R2, 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 IE update has been released in November or December 2025.
You can download the IE Cumulative Update for Windows Server 2012 R2 from the link shared below:
Download Cumulative Update for Internet Explorer – KB5066840 (54.9 MB)
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