Microsoft DWM Core Library Elevation of Privilege Vulnerability

cisa required action Apply updates per vendor instructions.

1. 2021-06-08 Published
2. 2021-11-03 Added to CISA KEV
3. 2021-11-17 CISA patch deadline
4. 2024-03-20 CISA SSVC: exploitation active

Added

5 y ago (2021-11-03)

Patch by

2021-11-17 (4 y ago)

Ransomware

Not known

Required action

Apply updates per vendor instructions.

Vendor, product

Microsoft, Windows

CISA name

Microsoft Desktop Window Manager (DWM) Core Library Privilege Escalation Vulnerability

How it is exploited and what it leads to, in MITRE ATT&CK terms.

• T1598.002 Spearphishing Attachment exploitation
• T1068 Exploitation for Privilege Escalation primary impact

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

Exploitation

Active, exploited in the wild

Automatable

no

Technical impact

total

Assessed

2 y ago (2024-03-20)

6.61% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

• 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

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

  patch, vendor-advisory

• cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33739

  government-resource, us-government-resource

• CVE List CVE-2021-33739
• NVD CVE-2021-33739

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.