Junglewise Threat Intelligence

CVE-2021-36955: Microsoft Windows Common Log File System (CLFS) Driver Privilege Escalation Vulnerability

CVE-2021-36955 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2021-11-03

Technologies: Microsoft Windows Server 2008, Microsoft Windows, Microsoft Windows 8.1, Microsoft Windows Server 2022, Microsoft Windows Server 2019, Microsoft Windows Server 2016, Microsoft Windows 7, Microsoft Windows 10, Microsoft Windows Server 2012, Microsoft Windows Rt 8.1. Vendors: Microsoft.

Executive brief

The Microsoft Windows Common Log File System (CLFS) driver contains an elevation of privilege vulnerability. An attacker who successfully exploits this vulnerability could gain SYSTEM privileges on the affected system. This vulnerability has been observed being exploited in the wild.

Affected products

  • Microsoft Windows 10 1507, 1607, 1809, 1909, 2004, 20H2, 21H1
  • Microsoft Windows 7 SP1
  • Microsoft Windows 8.1
  • Microsoft Windows RT 8.1
  • Microsoft Windows Server 2008 SP2, R2 SP1
  • Microsoft Windows Server 2012 R2
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2022
  • Microsoft Windows Server 2004
  • Microsoft Windows Server 20H2

Timeline

  • 2021-09-24: disclosed: Initial analysis by NIST
  • 2021-11-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog
  • 2021-11-03: advisory: Published date reported in advisory summary

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