Local privilege escalation via undisclosed access control flaw
Published May 13, 2025 · Updated Feb 26, 2026
Improper access control in Microsoft Azure File Sync before build 26100 allows local users to elevate privileges on Windows Server. Microsoft has not disclosed the affected component or the operation that applies access controls incorrectly to attacker-controlled input. Exploitation requires existing low-privileged local access and high-complexity conditions; successful exploitation grants elevated rights with broad system impact.
Summary
What happened
Improper access control in Microsoft Azure File Sync before build 26100 allows local users to elevate privileges on Windows Server. Microsoft has not disclosed the affected component or the operation that applies access controls incorrectly to attacker-controlled input. Exploitation requires existing low-privileged local access and high-complexity conditions; successful exploitation grants elevated rights with broad system impact.
The record
- CVE
- CVE-2025-29973
- Published
- May 13, 2025
- Updated
- Feb 26, 2026
- Vendor
- Microsoft
- Product
- Azure File Sync
- Classifications
- CWE-284, T1068
- Attack vector
- local
- Privileges
- authenticated
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=1.0.0 <26100
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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