SYSTEM privilege escalation via stale tracker pointers
Published Jun 8, 2021 · Updated Oct 21, 2025
Privilege escalation in Microsoft DWM Core Library on affected Windows 10 and Server builds allows local users to obtain SYSTEM rights. A DirectComposition binding manager retains pointers to freed interaction-tracker marshalers, then dereferences attacker-replaced objects during a channel commit. Local code can convert the use-after-free into a kernel write and alter thread state, giving the originating process SYSTEM-level control.
Summary
What happened
Privilege escalation in Microsoft DWM Core Library on affected Windows 10 and Server builds allows local users to obtain SYSTEM rights. A DirectComposition binding manager retains pointers to freed interaction-tracker marshalers, then dereferences attacker-replaced objects during a channel commit. Local code can convert the use-after-free into a kernel write and alter thread state, giving the originating process SYSTEM-level control.
The record
- CVE
- CVE-2021-33739
- Published
- Jun 8, 2021
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Windows 10 Version 21H1
- Classifications
- T1068
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 8, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.0 <10.0.19043.1052
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.
Weakness, pattern, technique
Public exploit references
- mavillon1 CVE-2021-33739 POCfunctional · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities listingknown exploited catalog
Technologies
Your stack
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Your stack
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