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Windows 10 1607Operating system · Microsoft

CVE-2025-30385

HIGH · 7.8 CVSS v3.1 Published 2025-05-13
Fix available
A fix is available. Upgrade to 10.0.14393.8066 / 10.0.17763.7314 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
Use after free in Windows Common Log File System Driver 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 confidence

A use-after-free vulnerability exists in the Windows Common Log File System Driver (CLFS.sys), a kernel-mode logging infrastructure component. An authenticated local attacker can exploit this memory corruption flaw to achieve privilege escalation from a lower-privileged account to elevated (SYSTEM) privileges.

MitigationApply the Microsoft security update for CVE-2025-30385 from the May 2025 patch cycle to address the use-after-free in CLFS.sys; verify the patch deployment across affected Windows systems.

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
Windows 10 1607Operating system
Affected:< 10.0.14393.8066
Windows 10 1809Operating system
Affected:< 10.0.17763.7314
Windows 10 21h2Operating system
Affected:< 10.0.19044.5854
Windows 10 22h2Operating system
Affected:< 10.0.19045.5854
Windows 11 22h2Operating system
Affected:< 10.0.22621.5335
Windows 11 23h2Operating system
Affected:< 10.0.22631.5335
Windows 11 24h2Operating system
Affected:< 10.0.26100.4061
Windows Server 2008Operating system
Affected:all versions= r2

CVSS 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
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Windows version and build number
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to get the exact Windows edition, version, and build number
    Affected if The build number falls below the fixed thresholds: < 14393.8066 (Win 10 1607), < 17763.7314 (Win 10 1809), < 19044.5854 (Win 10 21h2), < 19045.5854 (Win 10 22h2), < 22621.5335 (Win 11 22h2), < 22631.5335 (Win 11 23h2), < 26100.4061 (Win 11 24h2), or is any version of Windows Server 2008 R2
  2. Check CLFS.sys driver file version
    Navigate to C:\Windows\System32\drivers\clfs.sys, right-click Properties, and check the File Version field, or run 'driverquery /v /fo list | findstr -i clfs'
    Affected if The driver file version is lower than the version bundled with the May 2025 security update for your Windows build; file version typically matches the OS build number
  3. Verify May 2025 security update installation
    Run 'wmic qfe list' or 'Get-HotFix | Where-Object {$_.InstalledOn -ge "05/01/2025"}' to list hotfixes installed in May 2025 or later
    Affected if No security update from the May 2025 patch cycle (KB50xxxx) is listed that addresses CVE-2025-30385
  4. Confirm CLFS logging is in use
    Check for presence of .blf and .log files in application directories (common CLFS log locations) or review application documentation for CLFS usage; CLFS is a kernel service that may be used by various applications
    Affected if Any application on the system uses the Common Log File System for logging; the vulnerability is in the kernel driver itself, so presence of CLFS logs indicates active usage

The system is affected if it runs a Windows version with a build number below the fixed thresholds AND lacks the May 2025 security update for CVE-2025-30385, regardless of whether CLFS logs are actively present since the vulnerable driver loads with the OS.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 10.0.14393.8066 / 10.0.17763.7314 / 10.0.19044.5854 or later
Fixed in 10.0.14393.806610.0.17763.731410.0.19044.5854
Interim mitigation

Apply the Microsoft security update for CVE-2025-30385 from the May 2025 patch cycle to address the use-after-free in CLFS.sys; verify the patch deployment across affected Windows systems.

Recommended fix High confidence

Windows 10 1607: 10.0.14393.8066 or later | Windows 10 1809: 10.0.17763.7314 or later | Windows 10 21h2: 10.0.19044.5854 or later | Windows 10 22h2: 10.0.19045.5854 or later | Windows 11 22h2: 10.0.22621.5335 or later | Windows 11 23h2: 10.0.22631.5335 or later | Windows 11 24h2: 10.0.26100.4061 or

  1. Identify the current Windows version by running 'winver' or 'systeminfo' from command prompt
  2. For Windows 10 1607: Install KB5055523 (10.0.14393.8066)
  3. For Windows 10 1809: Install KB5055518 (10.0.17763.7314)
  4. For Windows 10 21h2: Install KB5055525 (10.0.19044.5854)
  5. For Windows 10 22h2: Install KB5055526 (10.0.19045.5854)
  6. For Windows 11 22h2: Install KB5055527 (10.0.22621.5335)
  7. For Windows 11 23h2: Install KB5055527 (10.0.22631.5335)
  8. For Windows 11 24h2: Install KB5055527 (10.0.26100.4061)
Caveat Windows Server 2008 R2 is end-of-life with no patch; requires system replacement

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 10 1607 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-30385 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data