CVE-2025-21311: Microsoft Windows 11 24h2

Critical severity, CVSS 9.8. EPSS: 2.2% chance of exploitation in the next 30 days.

Windows NTLM V1 Elevation of Privilege Vulnerability

Affected products

• Microsoft Windows 11 24h2: before 10.0.26100.2894 (fixed in 10.0.26100.2894)
• Microsoft Windows Server 2022 23h2: before 10.0.25398.1369 (fixed in 10.0.25398.1369)
• Microsoft Windows Server 2025: before 10.0.26100.2894 (fixed in 10.0.26100.2894)

Published 2025-01-14. Last modified 2026-06-17.