CVE-2021-43226

HighActively exploited (CISA KEV)Known to be used in ransomware campaigns

Description

Windows Common Log File System Driver Elevation of Privilege Vulnerability

SeverityHigh
CVSS7.8
Exploit probability—
ProductMicrosoft Windows
PublishedDec 15, 2021
First seenDec 15, 2021
Added to KEVOct 6, 2025

How to fix

CISA 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 due date: Oct 27, 2025
Update
  • microsoft windows_10_150710.0.10240.19145 or later
  • microsoft windows_10_160710.0.14393.4825 or later
  • microsoft windows_10_180910.0.17763.2366 or later
  • microsoft windows_10_190910.0.18363.1977 or later
  • microsoft windows_10_200410.0.19041.1415 or later
  • microsoft windows_10_20h210.0.19042.1415 or later
  • microsoft windows_10_21h110.0.19043.1415 or later
  • microsoft windows_10_21h210.0.19044.1415 or later
  • microsoft windows_11_21h210.0.22000.376 or later
  • microsoft windows_server_200410.0.19041.1415 or later
  • microsoft windows_server_201610.0.14393.4825 or later
  • microsoft windows_server_201910.0.17763.2366 or later

Affected products

ProductAffected versionsFixed in
microsoft windows_10_1507v < 10.0.10240.1914510.0.10240.19145
microsoft windows_10_1607v < 10.0.14393.482510.0.14393.4825
microsoft windows_10_1809v < 10.0.17763.236610.0.17763.2366
microsoft windows_10_1909v < 10.0.18363.197710.0.18363.1977
microsoft windows_10_2004v < 10.0.19041.141510.0.19041.1415
microsoft windows_10_20h2v < 10.0.19042.141510.0.19042.1415
microsoft windows_10_21h1v < 10.0.19043.141510.0.19043.1415
microsoft windows_10_21h2v < 10.0.19044.141510.0.19044.1415
microsoft windows_11_21h2v < 10.0.22000.37610.0.22000.376
microsoft windows_7No range specified—
microsoft windows_8.1No range specified—
microsoft windows_rt_8.1No range specified—
microsoft windows_server_2004v < 10.0.19041.141510.0.19041.1415
microsoft windows_server_2008No range specified, r2—
microsoft windows_server_2012No range specified, r2—
microsoft windows_server_2016v < 10.0.14393.482510.0.14393.4825
microsoft windows_server_2019v < 10.0.17763.236610.0.17763.2366
microsoft windows_server_2022v < 10.0.20348.40510.0.20348.405
microsoft windows_server_20h2v < 10.0.19042.141510.0.19042.1415

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

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