Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

CVE record · CVE-2021-34527

Windows Print Spooler Remote Code Execution Vulnerability

CVSS 8.8 HighCriticalIn CISA KEV · ransomwareEPSS 1.00 · 99th percentile

Critical, because:

  • In CISA’s KEV catalogue since 3 Nov 2021: it is known to be exploited.
  • CVSS score 8.8 (7.0 or more) and EPSS 1.00 (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 2 Jul 2021, 21:25 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 10 Version 1507
  • affected 10.0.10240.0 to before 10.0.10240.18969 custom
Microsoft Windows 10 Version 1607
  • affected 10.0.14393.0 to before 10.0.14393.4470 custom
Microsoft Windows 10 Version 1809
  • affected 10.0.17763.0 to before 10.0.17763.2029 custom
Microsoft Windows 10 Version 1809
  • affected 10.0.0 to before 10.0.17763.2029 custom
Microsoft Windows 10 Version 20H2
  • affected 10.0.0 to before 10.0.19042.1083 custom
Microsoft Windows 10 Version 21H2
  • affected 10.0.19044.0 to before 10.0.19044.1415 custom
Microsoft Windows 10 Version 22H2
  • affected 10.0.19045.0 to before 10.0.19045.2251 custom
Microsoft Windows 11 version 21H2
  • affected 10.0.22000.0 to before 10.0.22000.318 custom
Microsoft Windows 11 version 22H2
  • affected 10.0.22621.0 to before 10.0.22621.674 custom
Microsoft Windows 8.1
  • affected 6.3.0 to before 6.3.9600.20046 custom
Microsoft Windows Server 2008 R2 Service Pack 1
  • affected 6.1.7601.0 to before 6.1.7601.25633 custom
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)
  • affected 6.1.7601.0 to before 6.1.7601.25633 custom
Microsoft Windows Server 2008 Service Pack 2
  • affected 6.0.6003.0 to before 6.0.6003.21138 custom
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)
  • affected 6.0.6003.0 to before 6.0.6003.21138 custom
Microsoft Windows Server 2012
  • affected 6.2.9200.0 to before 6.2.9200.23383 custom
Microsoft Windows Server 2012 (Server Core installation)
  • affected 6.2.9200.0 to before 6.2.9200.23383 custom
Microsoft Windows Server 2012 R2
  • affected 6.3.9600.0 to before 6.3.9600.20046 custom
Microsoft Windows Server 2012 R2 (Server Core installation)
  • affected 6.3.9600.0 to before 6.3.9600.20046 custom
Microsoft Windows Server 2016
  • affected 10.0.14393.0 to before 10.0.14393.4470 custom
Microsoft Windows Server 2016 (Server Core installation)
  • affected 10.0.14393.0 to before 10.0.14393.4470 custom
Microsoft Windows Server 2019
  • affected 10.0.17763.0 to before 10.0.17763.2029 custom
Microsoft Windows Server 2019 (Server Core installation)
  • affected 10.0.17763.0 to before 10.0.17763.2029 custom
Microsoft Windows Server 2022
  • affected 10.0.20348.0 to before 10.0.20348.230 custom
Microsoft Windows Server version 20H2
  • affected 10.0.0 to before 10.0.19042.1083 custom
Identifiers
CVE-2021-34527
CNA
microsoft
Tags
Published
2 Jul 2021
Updated
10 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
8.8 High 3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C CNA (microsoft)
  • CISA KEV Listed since 3 Nov 2021: known to be exploited. CISA reports use in ransomware campaigns.
  • EPSS 1.00, the 99th percentile, on 9 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 2 Jul 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.