CVE-2021-31956 kev in the critical feed json
Windows NTFS Elevation of Privilege Vulnerability
published 2021-06-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18829
- cvss
- 7.8
- version 3.1, CNA
- cisa kev
- Exploited
- added 2021-11-03
- epss
- 22.3%
- EPSS 22.3% chance of exploitation in 30 days, percentile 97%
- public exploits
- 0
- none known
Summary
Windows NTFS Elevation of Privilege Vulnerability
Patch / fix
cisa required action Apply updates per vendor instructions.
- 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
Timeline
- Found exploited as a 0-day (Project Zero)
- 0-day patched (Project Zero)
- Published
- Added to CISA KEV
- CISA patch deadline
- CISA SSVC: exploitation active
Known exploited
- Added
- 5 y ago
- Patch by
- 2021-11-17 (4 y ago)
- Ransomware
- Not known
- Required action
- Apply updates per vendor instructions.
- Vendor, product
- Microsoft, Windows
- CISA name
- Microsoft Windows NTFS Privilege Escalation Vulnerability
Zero-day
Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.
- Found
- 2021-04-14
- Patched
- 2021-06-08
- Details
- project zero tracker
CISA SSVC
- Exploitation
- Active, exploited in the wild
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
22.27% chance of exploitation in the next 30 days, higher than 97% 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:F/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 | 9.3 | AV:N/AC:M/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-191 Integer Underflow (Wrap or Wraparound)
References
-
portal.msrc.microsoft.com
/en-US/security-guidance/advisory/CVE-2021-31956
patch, vendor-advisory
-
cisa.gov
/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31956
government-resource, us-government-resource
Sources
- CVE List CVE-2021-31956
- NVD CVE-2021-31956
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.