CVE WatchAug 10, 2026

CVE-2021-36955

Microsoft Windows Common Log File System (CLFS) Driver Privilege Escalation Vulnerability

CVSS

7.8

High

EPSS

4.1%

p91

KEV

YES

Nov 3, 2021

Exploit Today

0-100

Published: Sep 15, 2021 · Last modified: Aug 10, 2026

EPSS · 30d

4.0%EPSS · 30 days4.1%

2026-09-172026-10-15

KEV catalog record

Product

Microsoft / Windows

Vulnerability

Microsoft Windows Common Log File System (CLFS) Driver Privilege Escalation Vulnerability

Added to KEV

Nov 3, 2021

Remediate by

Nov 17, 2021

Known ransomware use

Yes

Summary 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.

Notes

https://nvd.nist.gov/vuln/detail/CVE-2021-36955

Technical description

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Official references

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