CVE record · CVE-2021-33739

Microsoft DWM Core Library Elevation of Privilege Vulnerability

CVSS 8.4 HighCriticalIn CISA KEVEPSS 0.066 · 93rd percentile

Critical, because:

In CISA’s KEV catalogue since 3 Nov 2021: it is known to be exploited.

Published by the CVE Program (CNA: microsoft) at 8 Jun 2021, 22:46 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
Vendor	Product	Versions
Microsoft	Windows 10 Version 1909	affected 10.0.0 to before 10.0.18363.1621 custom
Microsoft	Windows 10 Version 21H1	affected 10.0.0 to before 10.0.19043.1052 custom
Microsoft	Windows 10 Version 2004	affected 10.0.0 to before 10.0.19041.1052 custom
Microsoft	Windows Server version 2004	affected 10.0.0 to before 10.0.19041.1052 custom
Microsoft	Windows 10 Version 20H2	affected 10.0.0 to before 10.0.19042.1052 custom
Microsoft	Windows Server version 20H2	affected 10.0.0 to before 10.0.19042.1052 custom

Identifiers: CVE-2021-33739
CNA: microsoft
Tags: Microsoft Windows 10 Version 1909
Microsoft Windows 10 Version 21H1
Microsoft Windows 10 Version 2004
Microsoft Windows Server version 2004
Microsoft Windows 10 Version 20H2
Microsoft Windows Server version 20H2
Published: 8 Jun 2021
Updated: 21 Oct 2025

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

Score	Rating	CVSS	Vector	Source
8.4	High	3.1	CVSS:3.1/AV:L/AC:L/PR:N/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.
EPSS 0.066, the 93rd 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 8 Jun 2021. New records show when each source confirmed them.

Sources

References from the CNA

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33739

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.