Improper access control in Microsoft Windows - CVE-2026-66804
Published: August 12, 2026 / Updated: September 4, 2026
Vulnerability identifier: #VU141866
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-66804
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability:
Public exploit is available
Vulnerability details
The vulnerability allows a local user to elevate privileges.
The vulnerability exists due to improper access control in Windows Cross Device Service when handling local access to the service. A local user can exploit the access control weakness to elevate privileges.
Successful exploitation could result in SYSTEM privileges.
Affected software
Microsoft Windows
How to mitigate CVE-2026-66804
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 22H2 10.0.19045.7663, 11 24H2 10.0.26100.9106, 11 24H2 10.0.26100.9168, 11 25H2 10.0.26200.9168, 11 26H1 10.0.28000.2704