Summary
Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
For an attacker to exploit this vulnerability, they would need to have knowledge of a specific operation that triggers a memory allocation failure, specifically a use after free.
What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.
Security updates
10.0.20348.4648 — https://support.microsoft.com/help/5073457
10.0.19044.6809 — https://support.microsoft.com/help/5073724
10.0.26100.32230 — https://support.microsoft.com/en-us/topic/a6021fd2-b3b7-45a7-b68e-35c28a2a77da
10.0.26200.7623 — https://support.microsoft.com/help/5074109
10.0.22631.6491 — https://support.microsoft.com/help/5073455
10.0.25398.2092 — https://support.microsoft.com/help/5073450
Vulnerabilities 1
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High 7.0
Microsoft DWM Core Library Elevation of Privilege Vulnerability
Use after free in Windows DWM allows an authorized attacker to elevate privileges locally.
Revision history
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#1
Information published.
References
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CVE-2026-20842 Microsoft DWM Core Library Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20842
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss