CVE-2026-66804 Microsoft Windows Cross Device Service Elevation of Privilege Vulnerability
An authorized local attacker can elevate privileges due to improper access control in the Windows Cross Device Service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66804?
CVE-2026-66804 is a high-severity vulnerability in Microsoft Windows 10 22h2, published on 11 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Improper access control in Windows Cross Device Service allows an authorized attacker to elevate privileges locally.
Weakness: CWE-284
Which versions are affected by CVE-2026-66804?
It affects 4 products.
Products include Microsoft Windows 10 22h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1.
How do I fix CVE-2026-66804?
No fix has been published for CVE-2026-66804 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-66804 being exploited?
There is no known exploitation of CVE-2026-66804 in the wild and no public exploit code.
Public exploit code: 4 proofs of concept on GitHub.
Sources
Also known as GHSA-m9fr-m5pc-g6ww.