Local privilege escalation via Win32K race condition
Published May 12, 2026 · Updated May 12, 2026
Race condition in Microsoft Windows Win32K GRFX allows local users with low privileges to elevate privileges on affected systems. Microsoft identifies improper synchronization of a shared resource, but has not published the affected function or the operations that race. Exploitation requires local low-privileged access and no user interaction, with successful exploitation compromising confidentiality, integrity, and availability.
Summary
What happened
Race condition in Microsoft Windows Win32K GRFX allows local users with low privileges to elevate privileges on affected systems. Microsoft identifies improper synchronization of a shared resource, but has not published the affected function or the operations that race. Exploitation requires local low-privileged access and no user interaction, with successful exploitation compromising confidentiality, integrity, and availability.
The record
- CVE
- CVE-2026-34330
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-416, CWE-190, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 12, 2026CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record 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=10.0.17763.0 <10.0.17763.8755
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
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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