CVE-2021-43226

HIGH severity · CVSS 7.8 · actively exploited (CISA KEV)

7.8CVSS HIGH ● exploited

🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities). Added to KEV 2025-10-06. US federal agencies must patch by 2025-10-27.

Summary

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Impact & exploitability

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)8%

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 2019 Windows Server 2022

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://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43226 ↗

Additional information

NVD record
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43226Patch
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43226Patch
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43226