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CVE record · CVE-2021-42278

Active Directory Domain Services Elevation of Privilege Vulnerability

CVSS 7.5 HighCriticalIn CISA KEV · ransomwareEPSS 0.73 · 99th percentile

Critical, because:

  • In CISA’s KEV catalogue since 11 Apr 2022: it is known to be exploited.
  • CVSS score 7.5 (7.0 or more) and EPSS 0.73 (0.1 or more): a high score and a real chance of exploitation in the next 30 days.

How we decide what’s critical

Published by the CVE Program (CNA: microsoft) at 10 Nov 2021, 00:47 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
VendorProductVersions
Microsoft Windows Server 2008 R2 Service Pack 1
  • affected 6.1.7601.0 to before 6.1.7601.25769 custom
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)
  • affected 6.1.7601.0 to before 6.1.7601.25769 custom
Microsoft Windows Server 2008 Service Pack 2
  • affected 6.0.6003.0 to before 6.0.6003.21282 custom
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)
  • affected 6.0.6003.0 to before 6.0.6003.21282 custom
Microsoft Windows Server 2012
  • affected 6.2.9200.0 to before 6.2.9200.23517 custom
Microsoft Windows Server 2012 (Server Core installation)
  • affected 6.2.9200.0 to before 6.2.9200.23517 custom
Microsoft Windows Server 2012 R2
  • affected 6.3.9600.0 to before 6.3.9600.20174 custom
Microsoft Windows Server 2012 R2 (Server Core installation)
  • affected 6.3.9600.0 to before 6.3.9600.20174 custom
Microsoft Windows Server 2016
  • affected 10.0.14393.0 to before 10.0.14393.4770 custom
Microsoft Windows Server 2016 (Server Core installation)
  • affected 10.0.14393.0 to before 10.0.14393.4770 custom
Microsoft Windows Server 2019
  • affected 10.0.17763.0 to before 10.0.17763.2300 custom
Microsoft Windows Server 2019 (Server Core installation)
  • affected 10.0.17763.0 to before 10.0.17763.2300 custom
Microsoft Windows Server 2022
  • affected 10.0.20348.0 to before 10.0.20348.350 custom
Microsoft Windows Server version 2004
  • affected 10.0.0 to before 10.0.19041.1348 custom
Microsoft Windows Server version 20H2
  • affected 10.0.0 to before 10.0.19042.1348 custom
Identifiers
CVE-2021-42278
CNA
microsoft
Tags
Published
10 Nov 2021
Updated
19 Aug 2026

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

ScoreRatingCVSSVectorSource
7.5 High 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C CNA (microsoft)
  • CISA KEV Listed since 11 Apr 2022: known to be exploited. CISA reports use in ransomware campaigns.
  • EPSS 0.73, the 99th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 10 Nov 2021. New records show when each source confirmed them.

Sources

References from the CNA

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.