CVE-2021-43226
Microsoft Windows Privilege Escalation Vulnerability
CVSS
7.8
High
EPSS
3.3%
p88
KEV
YES
Oct 6, 2025
Exploit Today
76
0-100
Published: Dec 15, 2021 · Last modified: Aug 22, 2026
Product
Microsoft / Windows
Vulnerability
Microsoft Windows Privilege Escalation Vulnerability
Added to KEV
Oct 6, 2025
Remediate by
Oct 27, 2025
Known ransomware use
Yes
Summary description
Microsoft Windows Common Log File System Driver contains a privilege escalation vulnerability that could allow a local, privileged attacker to bypass certain security mechanisms.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Notes
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43226 ; https://nvd.nist.gov/vuln/detail/CVE-2021-43226
Windows Common Log File System Driver Elevation of Privilege Vulnerability
- portal.msrc.microsoft.comhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43226
- portal.msrc.microsoft.comhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43226
- www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-43226