Cyber Resilience

CVE-2021-43226

Microsoft Windows Server 2008 r2

CISA KEVActive ExploitationEUVD Exploited
Published
15 December 2021
Modified
30 October 2025
KEV Added
06 October 2025
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.031 86th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2021-43226 is a high-severity an unspecified weakness vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.8 (High).

Operationally, ranked in the top 14% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

The vulnerability is an elevation of privilege flaw in the Windows Common Log File System Driver, assigned CVE-2021-43226 with a CVSS 3.1 base score of 7.8. It affects the Windows operating system component responsible for handling common log file system operations.

An attacker with local access and low privileges can exploit the issue without user interaction to obtain high impacts on confidentiality, integrity, and availability, enabling privilege escalation on the affected system.

Microsoft has published security guidance addressing the vulnerability through its advisory portal, and the flaw appears in CISA's catalog of known exploited vulnerabilities, indicating confirmed real-world exploitation activity.

EU & UK References

Vulnerability Data

Windows Common Log File System Driver Elevation of Privilege Vulnerability

CWE(s)
KEV Date Added
06 October 2025

Related Threats

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Affected Assets

microsoft
windows 10 1507
≤ 10.0.10240.19145 · ≤ 10.0.10240.19145
microsoft
windows 10 1607
≤ 10.0.14393.4825 · ≤ 10.0.14393.4825
microsoft
windows 10 1809
≤ 10.0.17763.2366
microsoft
windows 10 1909
≤ 10.0.18363.1977
microsoft
windows 10 2004
≤ 10.0.19041.1415
microsoft
windows 10 20h2
≤ 10.0.19042.1415 · ≤ 10.0.19042.1415
microsoft
windows 10 21h1
≤ 10.0.19043.1415
microsoft
windows 10 21h2
≤ 10.0.19044.1415
microsoft
windows 11 21h2
≤ 10.0.22000.376
microsoft
windows 7
all versions
+9 more product configuration(s) — see NVD for full list

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References