Actively exploitedKnown ransomware use

CVE-2022-24521 Microsoft Windows CLFS Driver Privilege Escalation Vulnerability

Microsoft Windows Common Log File System (CLFS) Driver contains an unspecified vulnerability that allows for privilege escalation.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 13 Apr 2022.
  • CISA lists it as known to be used in ransomware campaigns.
  • Rated High severity (CVSS 7.8, scored by Vendor).
  • It has been in the catalogue for 1,668 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Affected Versions

ProductVersions
Microsoft Windows 10 Version 180910.0.17763.0 to before 10.0.17763.2803
Microsoft Windows 10 Version 180910.0.0 to before 10.0.17763.2803
Microsoft Windows Server 201910.0.17763.0 to before 10.0.17763.2803
Microsoft Windows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.2803
Microsoft Windows 10 Version 190910.0.0 to before 10.0.18363.2212
Microsoft Windows 10 Version 21H110.0.0 to before 10.0.19043.1645

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Microsoft Windows. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Not Sure If You Are Exposed?

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