CVE-2025-21218: Microsoft Windows Server 2012

High severity, CVSS 7.5. EPSS: 2.6% chance of exploitation in the next 30 days.

Windows Kerberos Denial of Service Vulnerability

Affected products

• Microsoft Windows Server 2012: affected versions not specified; version r2 only
• Microsoft Windows Server 2016: before 10.0.14393.7699 (fixed in 10.0.14393.7699)
• Microsoft Windows Server 2019: before 10.0.17763.6775 (fixed in 10.0.17763.6775)
• Microsoft Windows Server 2022: before 10.0.20348.3091 (fixed in 10.0.20348.3091)
• 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.