SARA / Free Tools / CVE / CVE-2021-28310

CVE-2021-28310 — Microsoft Win32k Privilege Escalation Vulnerability

Win32k Elevation of Privilege Vulnerability

CVSS

7.8 HIGH

EPSS

27.82% (top 3.60%)

CWE

—

Published

2021-04-13T19:32:47.000Z

Last modified

2025-10-21T23:25:49.229Z

CVSS vector

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

CISA KEV — Actively Exploited

Added to KEV

2021-11-03

BOD 22-01 due

2021-11-17

Ransomware use

Unknown

View KEV detail

01What is this vulnerability?

Win32k Elevation of Privilege Vulnerability

Vendor	Product	Versions
Microsoft	Windows 10 Version 1803	10.0.0
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 Server, version 1909 (Server Core installation)	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

Yes — actively exploited. Added to the CISA KEV catalog on 2021-11-03. 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-2021-2831…

Want this in your SOAR or SIEM?
SARA's API returns EPSS, CVSS, KEV, and an analyst-grade summary in one call.