JPCERT-AT-2026-0003
JPCERT/CC
2026-02-12

I. Overview

Microsoft has released February 2026 Security Updates to address the vulnerabilities in their products. Attackers leveraging these vulnerabilities may be able to gain SYSTEM privileges, among other impacts.

Microsoft Corporation
February 2026 Security Updates
https://msrc.microsoft.com/update-guide/en-us/releaseNote/2026-Feb

According to Microsoft, among the vulnerabilities, the following vulnerability has been confirmed to be exploited in the wild. Please consider applying the security update programs by referring to the information provided by Microsoft.

CVE-2026-21510
Windows Shell Security Feature Bypass Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21510

CVE-2026-21513
MSHTML Framework Security Feature Bypass Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21513

CVE-2026-21514
Microsoft Word Security Feature Bypass Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21514

CVE-2026-21519
Desktop Window Manager Elevation of Privilege Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21519

CVE-2026-21525
Windows Remote Access Connection Manager Denial of Service Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21525

CVE-2026-21533
Windows Remote Desktop Services Elevation of Privilege Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-21533

II. Solution

Please apply the security update programs through Microsoft Update, Windows Update, etc.

Microsoft Update Catalog
https://www.catalog.update.microsoft.com/

Windows Update: FAQ
https://support.microsoft.com/en-us/help/12373/windows-update-faq

III. References

Microsoft Corporation
Release Notes
https://msrc.microsoft.com/update-guide/

If you have any information regarding this alert, please contact JPCERT/CC.

JPCERT Coordination Center (Early Warning Group)
MAIL: ew-info@jpcert.or.jp
https://www.jpcert.or.jp/english/