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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 May 2022.
Windows 10 1507Operating system · Microsoft

CVE-2019-1214

HIGH · 7.8 CVSS v3.1 Published 2019-09-11
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
96/100
Remediation priority · Urgent
In the wild Zero-click Patch available

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
An elevation of privilege vulnerability exists when the Windows Common Log File System (CLFS) driver improperly handles objects in memory, aka 'Windows Common Log File System Driver Elevation of Privilege Vulnerability'.

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 · high confidence

A local elevation of privilege vulnerability exists in the Windows Common Log File System (CLFS) driver. The driver improperly handles objects in memory, allowing a local attacker to execute arbitrary code with SYSTEM privileges by exploiting the memory corruption issue.

MitigationApply the Microsoft security update (KB4516045 or later cumulative update) to patch the CLFS driver vulnerability. In enterprise environments, test the patch thoroughly before deployment to ensure compatibility with line-of-business applications.

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 1507Operating system
Affected:all versions
Windows 10 1607Operating system
Affected:all versions
Windows 10 1703Operating system
Affected:all versions
Windows 10 1709Operating system
Affected:all versions
Windows 10 1803Operating system
Affected:all versions
Windows 10 1809Operating system
Affected:all versions
Windows 10 1903Operating system
Affected:all versions
Windows 7Operating system
Affected:all versions

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
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to determine the installed Windows edition and version.
    Affected if The version is Windows 10 1507, 1607, 1703, 1709, 1803, 1809, 1903, or Windows 7 (any edition).
  2. Verify CLFS driver presence
    Check that clfs.sys exists in the system directory by running 'dir C:\Windows\System32\drivers\clfs.sys'.
    Affected if The file exists on the system (this driver is present by default on affected Windows versions).
  3. Check CLFS driver file version
    Right-click clfs.sys in File Explorer, select Properties, then view the Details tab for the File version, or run 'powershell (Get-Item C:\Windows\System32\drivers\clfs.sys).VersionInfo.FileVersion'.
    Affected if The driver version is lower than the patched version released in August 2019 (KB4516045).
  4. Verify security update installation
    Run 'powershell Get-HotFix -Id KB4516045' or check Windows Update history for the presence of security update KB4516045 or a later cumulative update.
    Affected if The security update KB4516045 or a later cumulative update is NOT installed.

The system is affected if it runs an unpatched Windows 10 (versions 1507-1903) or Windows 7 and lacks the KB4516045 (August 2019) security update.

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
Patch available Apply the vendor patch
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Apply the Microsoft security update (KB4516045 or later cumulative update) to patch the CLFS driver vulnerability. In enterprise environments, test the patch thoroughly before deployment to ensure compatibility with line-of-business applications.

Recommended fix High confidence

Windows 10 1903 or later (with latest security updates applied)

  1. Apply the September 2019 Security Updates (KB4512577 for Windows 10 1809, KB4512941 for Windows 10 1903, or the appropriate KB for your version)
  2. Open Windows Update and check for updates, or manually download the appropriate security update from the Microsoft Update Catalog
  3. Restart the system after applying the update to ensure the CLFS driver patch takes effect
  4. Verify the patch was successfully installed by checking Windows Update history or using system information tools
Caveat Windows 7 extended support ended in January 2020; organizations need paid extended support contracts for continued patches

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

Fix this in Windows 10 1507 Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,040
Get it fixed fast

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,864.

Scan for this in your stack

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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-2019-1214 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