CVE-2021-42278

Microsoft Windows Server 2008 R2 Service Pack 1, Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation), Microsoft Windows Server 2008 Service Pack 2

Published 10 Nov 2021 · updated 19 Aug 2026 · Analyzed

7.5 High · CVSS 3.1, microsoft.com

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 11 Apr 2022, with a remediation deadline of 2 May 2022 for US federal agencies. It has been used in ransomware campaigns.

Required action: Apply updates per vendor instructions.

Description

Active Directory Domain Services Elevation of Privilege Vulnerability

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-42278 · Patch, Vendor Advisory
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278 · Patch, Vendor Advisory
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42278 · US Government Resource