MSRC-CVE-2026-85921 — Windows Secure Kernel Mode Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain Virtual Trust Level 1 (VTL1) privileges.

Security updates
10.0.28000.2956 — https://support.microsoft.com/help/5129194

Vulnerabilities 1

High 8.2

CVE-2026-85921

Windows Secure Kernel Mode Elevation of Privilege Vulnerability

Double free in Windows Secure Kernel Mode allows an authorized attacker to elevate privileges locally.

Microsoft Windows 11 version 26H1 Windows

Sep 14, 2026

Revision history

2026-09-27 #3
Acknowledgement Updated
2026-09-25 #2
Updated an acknowledgement. This is an informational change only.
2026-09-14 #1
Information published.

References

CVE-2026-85921 Windows Secure Kernel Mode Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85921
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss