Local code execution via VMBus TOCTOU race
Published May 13, 2025 · Updated Feb 26, 2026
A TOCTOU race in the Windows Virtual Machine Bus allows local users to execute code by changing state between a check and its use. Microsoft identifies the VMBus locus and race class but has not disclosed the checked resource, later use, or attacker-controlled state change. Exploitation requires local access, user interaction, and high attack complexity, and can cross a security boundary with high system impact.
Summary
What happened
A TOCTOU race in the Windows Virtual Machine Bus allows local users to execute code by changing state between a check and its use. Microsoft identifies the VMBus locus and race class but has not disclosed the checked resource, later use, or attacker-controlled state change. Exploitation requires local access, user interaction, and high attack complexity, and can cross a security boundary with high system impact.
The record
- CVE
- CVE-2025-29833
- Published
- May 13, 2025
- Updated
- Feb 26, 2026
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-367, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 13, 2025CVE publishedPublication date reported by the CVE source.
- Feb 26, 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=10.0.10240.0 <10.0.10240.21014
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.
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Technologies
Your stack
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Your stack
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