dbcve.org
Windows 10Operating system · Microsoft

CVE-2022-21897

HIGH · 7.8 CVSS v3.1 Published 2022-01-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
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

This is a local Elevation of Privilege vulnerability in the Windows Common Log File System (CLFS) driver (clfs.sys). The vulnerability allows a low-privileged authenticated attacker to gain SYSTEM-level privileges by exploiting a flaw in the kernel-mode driver.

MitigationApply the applicable Microsoft security update for this vulnerability through Windows Update or manual KB installation, then verify the patch version matches the fixed build.

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 10Operating system
Affected:all versions= 20h2= 21h1= 21h2= 1607= 1809= 1909
Windows 11Operating system
Affected:all versions
Windows 7Operating system
Affected:all versions
Windows 8.1Operating system
Affected:all versions
Windows Rt 8.1Operating system
Affected:all versions
Windows ServerOperating system
Affected:= 20h2= 2022
Windows Server 2008Operating system
Affected:all versions= r2
Windows Server 2012Operating 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. Check Windows build version
    Open Command Prompt or PowerShell and run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to identify the Windows version and build number
    Affected if The build version matches one of the affected versions listed (Windows 10 20h2, 21h1, 21h2, 1607, 1809, 1909; Windows 11 all; Windows 7 all; Windows 8.1 all; Windows Rt 8.1; Windows Server 20h2, 2022; Windows Server 2008, 2008 r2; Windows Server 2012, 2012 r2)
  2. Verify clfs.sys driver presence
    In PowerShell, run 'Get-Item C:\Windows\System32\clfs.sys' or from Command Prompt run 'dir C:\Windows\System32\clfs.sys' to confirm the driver file exists
    Affected if The clfs.sys driver file exists on the system (this driver is present by default on all affected Windows versions)
  3. Check clfs.sys driver version
    Right-click clfs.sys in File Explorer, go to Properties, then Details tab to view File Version; or run 'powershell (Get-Item C:\Windows\System32\clfs.sys).VersionInfo.FileVersion'
    Affected if The driver version is older than the patched version for this CVE (patched builds include Windows 10 21H2 KB5009557, Windows 11 KB5009566, and corresponding Server patches)

A system is affected if it runs a vulnerable Windows version/build AND has the clfs.sys driver present AND the driver version has not been updated to the patched version.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the applicable Microsoft security update for this vulnerability through Windows Update or manual KB installation, then verify the patch version matches the fixed build.

Recommended fix High confidence
  1. Check for and install the January 2022 Windows security update (KB5009543 or subsequent relevant update) via Windows Update
  2. Alternatively, download the appropriate security update from the Microsoft Update Catalog for your specific Windows version
  3. Restart the system after applying the update
  4. Verify the update is installed by checking Windows Update history for the CVE-2022-21897 patch

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

Fix this in Windows 10 Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-21897 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2022-21897 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