System privilege escalation via unchecked property index
Published Apr 13, 2021 · Updated Oct 21, 2025
Out-of-bounds write in Microsoft Windows Desktop Window Manager allows local users to execute code with system privileges. CPropertySet::UpdateProperty in dwmcore.dll uses an attacker-controlled propertyId without checking it against the property count, enabling a controlled write beyond the propertiesData buffer. Exploitation requires local low-privilege code to groom the dwm.exe heap and issue crafted DirectComposition commands; successful exploitation gains system-level execution.
Summary
What happened
Out-of-bounds write in Microsoft Windows Desktop Window Manager allows local users to execute code with system privileges. CPropertySet::UpdateProperty in dwmcore.dll uses an attacker-controlled propertyId without checking it against the property count, enabling a controlled write beyond the propertiesData buffer. Exploitation requires local low-privilege code to groom the dwm.exe heap and issue crafted DirectComposition commands; successful exploitation gains system-level execution.
The record
- CVE
- CVE-2021-28310
- Published
- Apr 13, 2021
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 13, 2021CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=10.0.0 <publication
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
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Reported exploitation
- BITTER-linked exploitationthreat actor
- CISA Known Exploited Vulnerabilities listingknown exploited catalog
Technologies
Your stack
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Your stack
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