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

High 8.2 Published 14 Sep 2026 Updated 14 Oct 2026

An authorized local attacker can exploit a double free in Windows Secure Kernel Mode to elevate privileges.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-85921?

CVE-2026-85921 is a high-severity use after free vulnerability in Microsoft Windows 11 26h1, published on 14 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

Weakness: CWE-415

Which versions are affected by CVE-2026-85921?

It affects 1 product.

Products include Microsoft Windows 11 26h1.

How do I fix CVE-2026-85921?

No fix has been published for CVE-2026-85921 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-85921 being exploited?

There is no known exploitation of CVE-2026-85921 in the wild and no public exploit code.

All Microsoft Windows 11 26h1 vulnerabilities

Sources

Also known as GHSA-2q4x-w73p-vjf4.