CVE-2025-21418

HIGH severity · CVSS 7.8 · CWE-122 · actively exploited (CISA KEV)

7.8CVSS HIGH ● exploited

🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities). Added to KEV 2025-02-11. US federal agencies must patch by 2025-03-04.

Summary

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Impact & exploitability

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)10%

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products we track (2)

Windows Server 2022 Windows Server 2025

Recommendation

This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.

Official patch: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418 ↗

Additional information

NVD record
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418Patch
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21418