Live › vulnerability › CVE-2021-43226
Go to dashboardWindows Common Log File System (CLFS) driver has a privilege escalation flaw that lets a local user with some access gain higher privileges. CISA lists it as actively exploited, with ransomware use noted in the catalog.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| Microsoft Windows | vendor | – | – |
| microsoft windows 10 1507 | vendor | < 10.0.10240.19145 | 10.0.10240.19145 |
| microsoft windows 10 1607 | vendor | < 10.0.14393.4825 | 10.0.14393.4825 |
| microsoft windows 10 1809 | vendor | < 10.0.17763.2366 | 10.0.17763.2366 |
| microsoft windows 10 1909 | vendor | < 10.0.18363.1977 | 10.0.18363.1977 |
| microsoft windows 10 2004 | vendor | < 10.0.19041.1415 | 10.0.19041.1415 |
| microsoft windows 10 20h2 | vendor | < 10.0.19042.1415 | 10.0.19042.1415 |
| microsoft windows 10 21h1 | vendor | < 10.0.19043.1415 | 10.0.19043.1415 |
| microsoft windows 10 21h2 | vendor | < 10.0.19044.1415 | 10.0.19044.1415 |
| microsoft windows 11 21h2 | vendor | < 10.0.22000.376 | 10.0.22000.376 |
| microsoft windows 7 | vendor | – | – |
| microsoft windows 8.1 | vendor | – | – |
| microsoft windows rt 8.1 | vendor | – | – |
| microsoft windows server 2004 | vendor | < 10.0.19041.1415 | 10.0.19041.1415 |
| microsoft windows server 2008 | vendor | – | – |
| microsoft windows server 2008 | vendor | = r2 | – |
| microsoft windows server 2012 | vendor | – | – |
| microsoft windows server 2012 | vendor | = r2 | – |
| microsoft windows server 2016 | vendor | < 10.0.14393.4825 | 10.0.14393.4825 |
| microsoft windows server 2019 | vendor | < 10.0.17763.2366 | 10.0.17763.2366 |
| microsoft windows server 2022 | vendor | < 10.0.20348.405 | 10.0.20348.405 |
| microsoft windows server 20h2 | vendor | < 10.0.19042.1415 | 10.0.19042.1415 |
Unknown from the sources.
Apply the Microsoft patch for CVE-2021-43226 per vendor instructions; the sources do not name the KB or build numbers.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
Microsoft Windows Common Log File System Driver contains a privilege escalation vulnerability that could allow a local, privileged attacker to bypass certain security mechanisms.
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.
This page as .md · .json · in your agent: get_signal("CVE-2021-43226")
CISA KEV catalog, Creative Commons 0 · NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.