CVE-2025-29973
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper access control in Azure File Sync allows an authorized attacker to elevate privileges locally.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is an improper access control vulnerability in Azure File Sync that allows an already-authorized attacker to escalate their privileges locally on the affected system. The vulnerability stems from insufficient access control enforcement in the Azure File Sync agent, enabling a user with baseline access to gain higher-level privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 19.0.0.0= 20.0.0.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Verify Azure File Sync agent is installedOpen Registry Editor and navigate to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\AzureFileSync or check for the 'FileSyncSvc' Windows service in services.mscAffected if The agent is not present on the system, so this vulnerability does not apply
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Check Azure File Sync agent version via PowerShellRun Get-Service -Name FileSyncSvc | Select-Object Name,Status,StartType,@{n='Version';e={(Get-Item (Get-ItemProperty 'HKLM:\SYSTEM\CurrentControlSet\Services\FileSyncSvc').ImagePath).VersionInfo.FileVersion}} or check the file version of %ProgramFiles%\Azure\StorageSyncAgent\FileSyncSvc.exeAffected if The service is not running or the agent is not installed, indicating this specific attack surface is not present
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Confirm the exact installed version matches affected versionsCompare the obtained version number to the affected versions: exactly 19.0.0.0 or exactly 20.0.0.0Affected if The installed version is exactly 19.0.0.0 or 20.0.0.0 - these are the only versions confirmed vulnerable
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Verify local user context for privilege escalation riskCheck if the Azure File Sync agent runs under a service account with elevated privileges (examine the service Log On As setting in services.msc under FileSyncSvc properties)Affected if The agent runs under a high-privilege account (like SYSTEM or a domain admin) and the version is 19.0.0.0 or 20.0.0.0, making privilege escalation possible
A system is affected if Azure File Sync agent version 19.0.0.0 or 20.0.0.0 is installed and running, allowing a locally authenticated attacker with baseline user access to potentially elevate privileges.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply Microsoft security patches for Azure File Sync as soon as they become available. Review access controls on systems running Azure File Sync agents and limit local user privileges to the minimum necessary until the patch is applied.
- Consultation4.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-29973 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-29973 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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