November 3, 2021 · Applied Cybernetics Group
CVE-2021-36955 — Microsoft Windows
known ransomware use
Microsoft Windows Common Log File System (CLFS) Driver Privilege Escalation Vulnerability
- Added to KEV
2021-11-03- Federal due date
2021-11-17- Vendor
- Microsoft
- Product
- Windows
- EPSS
- 90.1th percentile (score 0.040, as of
2026-09-16) - NVD CVSS v3.1
- 7.8 (HIGH)
- Ransomware use
- Known
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2021-36955
CISA short description
Microsoft Windows Common Log File System (CLFS) driver contains an unspecified vulnerability that allows for privilege escalation.
Required action
Apply updates per vendor instructions.
NVD description
Windows Common Log File System Driver Elevation of Privilege Vulnerability