Skip to content
brandefense.io
Request A Demo
Vulnerability Intelligence

CVE-2021-43226

HighExploitedPublic exploit

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Published Dec 15, 2021 · Updated Aug 22, 2026

Key Facts

Patch immediately
  • CVE-2021-43226 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1507 (Microsoft), Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft) and 19 more products.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jun 13, 2022 and is known to be used in ransomware campaigns. Public exploit code is available.
  • EPSS estimates a 3.3% probability of exploitation in the next 30 days.
  • Fixed versions are available, including Windows 10 1507 10.0.10240.19145, Windows 10 1607 10.0.14393.4825, Windows 10 1809 10.0.17763.2366.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

7.8

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

3.3%

Higher than 88.2% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings, used by ransomware

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2021-43226 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

Windows Common Log File System Driver Elevation of Privilege Vulnerability

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVOct 6, 2025Oct 27, 2025Known
Industry KEV feedJun 13, 2022Oct 27, 2025Known
CIRCL KEVOct 6, 2025Oct 27, 2025Not reported
ENISA EUVDOct 6, 2025n/aNot reported

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.

Affected Products

62 affected entries in total
ProductAffected versionsFixed in
Windows 10 1507Microsoft10.0.10240.1914510.0.10240.19145
Windows 10 1607Microsoft10.0.14393.482510.0.14393.4825
Windows 10 1809Microsoft10.0.17763.2366, 10.0.18363.1977, 10.0.19041.141510.0.17763.2366
Windows 10 1909Microsoft10.0.18363.197710.0.18363.1977
Windows 10 2004MicrosoftSee advisory10.0.19041.1415
17 more affected products in the full CVE brief

Patched Releases

Windows 10 1507

10.0.10240.19145

Windows 10 1607

10.0.14393.4825

Windows 10 1809

10.0.17763.2366, 10.0.18363.1977, 10.0.19041.1415

Windows 10 1909

10.0.18363.1977

Windows 10 2004

10.0.19041.1415

windows 10 20H2

10.0.19042.1415

windows 10 21H1

10.0.19043.1415

windows 10 21H2

10.0.19044.1415

windows 11 21H2

10.0.22000.376

Windows 7

6.1.7601.25796

Windows 8.1

6.3.9600.20207

Windows Rt 8.1

6.3.9600.20207

Windows Server 2004

10.0.19041.1415

windows server 2008 R2

6.1.7601.25796

Windows Server 2008 Sp2

6.0.6003.21309

Windows Server 2012

6.2.9200.23540, 6.2.9200.23545

windows server 2012 R2

6.3.9600.20207

Windows Server 2016

10.0.14393.4825

Windows Server 2019

10.0.17763.2366

Windows Server 2022

10.0.20348.405

windows server 20H2

10.0.19042.1415

Timeline

  1. Publicly disclosed

    Dec 15, 2021

  2. Added to Industry KEV feed

    Jun 13, 2022

  3. Added to CISA KEV

    Oct 6, 2025

  4. Added to CIRCL KEV

    Oct 6, 2025

  5. Added to ENISA EUVD

    Oct 6, 2025

  6. Last updated

    Aug 22, 2026

References

3 more references in the full CVE brief

FAQ

Common Questions.

Is CVE-2021-43226 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.

Request A Demo