Windows Common Log File System Driver Elevation of Privilege Vulnerability

published 2021-06-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18827

cvss: 7.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits: 0; none known

Patch / fix

fixed in 25 links 1

Microsoft Windows 10 Version 1809 10.0.17763.1999
Microsoft Windows Server 2019 10.0.17763.1999
Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.1999
Microsoft Windows 10 Version 1909 10.0.18363.1621
Microsoft Windows 10 Version 21H1 10.0.19043.1052
Microsoft Windows 10 Version 2004 10.0.19041.1052
Microsoft Windows Server version 2004 10.0.19041.1052
Microsoft Windows 10 Version 20H2 10.0.19042.1052
Microsoft Windows Server version 20H2 10.0.19042.1052
Microsoft Windows 10 Version 1507 10.0.10240.18967
Microsoft Windows 10 Version 1607 10.0.14393.4467
Microsoft Windows Server 2016 10.0.14393.4467
Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.4467
Microsoft Windows 7 6.1.7601.25632
Microsoft Windows 7 Service Pack 1 6.1.7601.25632
Microsoft Windows 8.1 6.3.9600.20044, 6.3.9600.20045
Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21137
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.21137
Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21137
Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.25632
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.25632
Microsoft Windows Server 2012 6.2.9200.23372
Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.23372
Microsoft Windows Server 2012 R2 6.3.9600.20044, 6.3.9600.20045
Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.20044, 6.3.9600.20045

portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31954 advisory

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 2 y ago (2024-05-29)

Exploit prediction

1.06% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.2	AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

Microsoft Windows 10 Version 1809
Microsoft Windows Server 2019
Microsoft Windows Server 2019 (Server Core installation)
Microsoft Windows 10 Version 1909
Microsoft Windows 10 Version 21H1
Microsoft Windows 10 Version 2004
Microsoft Windows Server version 2004
Microsoft Windows 10 Version 20H2
Microsoft Windows Server version 20H2
Microsoft Windows 10 Version 1507
Microsoft Windows 10 Version 1607
Microsoft Windows Server 2016
Microsoft Windows Server 2016 (Server Core installation)
Microsoft Windows 7
Microsoft Windows 7 Service Pack 1
Microsoft Windows 8.1
Microsoft Windows Server 2008 Service Pack 2
Microsoft Windows Server 2008 Service Pack 2 (Server Core installation)
Microsoft Windows Server 2008 Service Pack 2
Microsoft Windows Server 2008 R2 Service Pack 1
Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation)
Microsoft Windows Server 2012
Microsoft Windows Server 2012 (Server Core installation)
Microsoft Windows Server 2012 R2
Microsoft Windows Server 2012 R2 (Server Core installation)

Classification

Weakness

CWE-122 Heap-based Buffer Overflow
CWE-269 Improper Privilege Management

References

portal.msrc.microsoft.com /en-US/security-guidance/advisory/CVE-2021-31954
patch, vendor-advisory
zerodayinitiative.com /advisories/ZDI-21-668/
third-party-advisory, vdb-entry

Sources

CVE List CVE-2021-31954
NVD CVE-2021-31954

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary