Oct 19, 2026 · 17:41 UTC SEARCH
UNRATED KNOWN EXPLOITED RANSOMWARE USE
Vulnerability intelligence

CVE-2021-43226

VendorMicrosoft
ProductWindows
Known exploitedYes
Added to CISA KEVOctober 6, 2025
KEV due dateOctober 27, 2025
Known ransomware useKnown

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.

CISA KEV status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities Catalog. Known ransomware campaign use: Known.

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