SARA / Free Tools / CVE / CVE-2021-34484

CVE-2021-34484 — Microsoft Windows User Profile Service Privilege Escalation Vulnerability

Windows User Profile Service Elevation of Privilege Vulnerability

CVSS

7.8 HIGH

EPSS

2.43% (top 15.00%)

CWE

—

Published

2021-08-12T18:11:55.000Z

Last modified

2025-10-21T23:25:38.781Z

CVSS vector

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

CISA KEV — Actively Exploited

Added to KEV

2022-03-31

BOD 22-01 due

2022-04-21

Ransomware use

Unknown

View KEV detail

01What is this vulnerability?

Windows User Profile Service Elevation of Privilege Vulnerability

Vendor	Product	Versions
Microsoft	Windows 10 Version 1809	10.0.0
Microsoft	Windows Server 2019	10.0.0
Microsoft	Windows Server 2019 (Server Core installation)	10.0.0
Microsoft	Windows 10 Version 1909	10.0.0
Microsoft	Windows 10 Version 21H1	10.0.0
Microsoft	Windows 10 Version 2004	10.0.0
Microsoft	Windows Server version 2004	10.0.0
Microsoft	Windows 10 Version 20H2	10.0.0
Microsoft	Windows Server version 20H2	10.0.0
Microsoft	Windows 10 Version 1507	10.0.0
Microsoft	Windows 10 Version 1607	10.0.0
Microsoft	Windows Server 2016	10.0.0
Microsoft	Windows Server 2016 (Server Core installation)	10.0.0
Microsoft	Windows 7	6.1.0
Microsoft	Windows 7 Service Pack 1	6.1.0
Microsoft	Windows 8.1	6.3.0
Microsoft	Windows Server 2008 Service Pack 2	6.0.0
Microsoft	Windows Server 2008 Service Pack 2 (Server Core installation)	6.0.0
Microsoft	Windows Server 2008 Service Pack 2	6.0.0
Microsoft	Windows Server 2008 R2 Service Pack 1	6.1.0
Microsoft	Windows Server 2008 R2 Service Pack 1 (Server Core installation)	6.0.0
Microsoft	Windows Server 2012	6.2.0
Microsoft	Windows Server 2012 (Server Core installation)	6.2.0
Microsoft	Windows Server 2012 R2	6.3.0
Microsoft	Windows Server 2012 R2 (Server Core installation)	6.3.0

Yes — actively exploited. Added to the CISA KEV catalog on 2022-03-31. Ransomware use: Unknown.

Patch to a fixed version listed in the vendor advisory (see references below).
Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
Hunt historical logs for exploitation indicators — see Detection signatures below.

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

portal.msrc.microsoft.com — https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-3448…

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