CVE-2021-36955
HighExploitedPublic exploitWindows Common Log File System Driver Elevation of Privilege Vulnerability
Published Sep 15, 2021 · Updated Aug 10, 2026
Key Facts
Patch immediately- CVE-2021-36955 is a high-severity vulnerability (CVSS 7.8 v3.1) affecting Windows 10 1507 (Microsoft), Windows 10 1607 (Microsoft), Windows 10 1809 (Microsoft) and 17 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 3, 2021 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 4.1% probability of exploitation in the next 30 days.
- Fixed versions are available, including Windows 10 1507 10.0.10240.19060, Windows 10 1607 10.0.14393.4651, Windows 10 1809 10.0.17763.2183.
- 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)
4.1%
Higher than 90.5% 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-2021-36955 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
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | Nov 17, 2021 | Known |
| Industry KEV feed | Nov 3, 2021 | Nov 17, 2021 | Known |
| CIRCL KEV | Nov 3, 2021 | Nov 17, 2021 | Known |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
50 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Windows 10 1507Microsoft | 10.0.10240.19060 | 10.0.10240.19060 |
| Windows 10 1607Microsoft | 10.0.14393.4651 | 10.0.14393.4651 |
| Windows 10 1809Microsoft | 10.0.17763.2183, 10.0.18363.1801, 10.0.19041.1237 | 10.0.17763.2183 |
| Windows 10 1909Microsoft | 10.0.18363.1801 | 10.0.18363.1801 |
| Windows 10 2004Microsoft | See advisory | 10.0.19041.1237 |
Patched Releases
Windows 10 1507
10.0.10240.19060
Windows 10 1607
10.0.14393.4651
Windows 10 1809
10.0.17763.2183, 10.0.18363.1801, 10.0.19041.1237
Windows 10 1909
10.0.18363.1801
Windows 10 2004
10.0.19041.1237
windows 10 20H2
10.0.19042.1237
windows 10 21H1
10.0.19043.1237
Windows 7
6.1.7601.25712
Windows 8.1
6.3.9600.20120
Windows Rt 8.1
6.3.9600.20120
Windows Server 2004
10.0.19041.1237
windows server 2008 R2
6.1.7601.25712
Windows Server 2008 Sp2
6.0.6003.21218
Windows Server 2012
6.2.9200.23462
windows server 2012 R2
6.3.9600.20120
Windows Server 2016
10.0.14393.4651
Windows Server 2019
10.0.17763.2183
Windows Server 2022
10.0.20348.230
windows server 20H2
10.0.19042.1237
Timeline
Publicly disclosed
Sep 15, 2021
Added to CISA KEV
Nov 3, 2021
Added to Industry KEV feed
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Aug 10, 2026
References
- advisoryhttps://blog.talosintelligence.com/2021/09/microsoft-patch-tuesday-for-sept-2021.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+feedburner%2FTalos+%28Talos%E2%84%A2+Blog%29
- advisoryhttps://isc.sans.edu/diary/rss/27834
- advisoryhttps://securityboulevard.com/2021/09/september-2021-patch-tuesday-comes-with-fixes-for-86-vulnerabilities-including-two-zero-days/
- advisoryhttps://us-cert.cisa.gov/
- advisoryhttps://us-cert.cisa.gov/ncas/current-activity/2021/09/14/microsoft-releases-september-2021-security-updates
FAQ
Common Questions.
Windows Common Log File System Driver Elevation of Privilege Vulnerability
Affected: Windows 10 1507 (Microsoft) versions 10.0.10240.19060; Windows 10 1607 (Microsoft) versions 10.0.14393.4651; Windows 10 1809 (Microsoft) versions 10.0.17763.2183, 10.0.18363.1801, 10.0.19041.1237, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Nov 3, 2021 and is known to be used in ransomware campaigns.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.
Public exploit code is available.
Fixed versions are available, including Windows 10 1507 10.0.10240.19060, Windows 10 1607 10.0.14393.4651, Windows 10 1809 10.0.17763.2183.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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