# CVE-2021-31956

Windows NTFS Elevation of Privilege Vulnerability

- Page: https://www.vulneraibility.com/cve/CVE-2021-31956
- CVSS: 7.8
- Known exploited: yes, in CISA KEV since 2021-11-03; CISA due date 2021-11-17
- EPSS: 22.27% (percentile 97.7)
- Unvetted proof-of-concept code on GitHub: 6 GitHub proofs of concept (first 2021-11-22)
- CISA SSVC: exploitation active, automatable no, technical impact total (assessed 2024-07-26)
- Weakness: CWE-191
- Published: 2021-06-08

## Affected versions

- Microsoft Windows 10 Version 1507: affected >= 10.0.0 and < 10.0.10240.18967
- Microsoft Windows 10 Version 1607: affected >= 10.0.0 and < 10.0.14393.4467
- Microsoft Windows 10 Version 1809: affected >= 10.0.0 and < 10.0.17763.1999
- Microsoft Windows 10 Version 1909: affected >= 10.0.0 and < 10.0.18363.1621
- Microsoft Windows 10 Version 2004: affected >= 10.0.0 and < 10.0.19041.1052
- Microsoft Windows 10 Version 20H2: affected >= 10.0.0 and < 10.0.19042.1052
- Microsoft Windows 10 Version 21H1: affected >= 10.0.0 and < 10.0.19043.1052
- Microsoft Windows 7: affected >= 6.1.0 and < 6.1.7601.25632
- Microsoft Windows 7 Service Pack 1: affected >= 6.1.0 and < 6.1.7601.25632
- Microsoft Windows 8.1: affected >= 6.3.0 and < 6.3.9600.20045; >= 6.3.0 and < 6.3.9600.20044
- Microsoft Windows Server 2008 R2 Service Pack 1: affected >= 6.1.0 and < 6.1.7601.25632
- Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation): affected >= 6.0.0 and < 6.1.7601.25632
- Microsoft Windows Server 2008 Service Pack 2: affected >= 6.0.0 and < 6.0.6003.21137
- Microsoft Windows Server 2008  Service Pack 2: affected >= 6.0.0 and < 6.0.6003.21137
- Microsoft Windows Server 2008 Service Pack 2 (Server Core installation): affected >= 6.0.0 and < 6.0.6003.21137
- Microsoft Windows Server 2012: affected >= 6.2.0 and < 6.2.9200.23372
- Microsoft Windows Server 2012 R2: affected >= 6.3.0 and < 6.3.9600.20045; >= 6.3.0 and < 6.3.9600.20044
- Microsoft Windows Server 2012 R2 (Server Core installation): affected >= 6.3.0 and < 6.3.9600.20045; >= 6.3.0 and < 6.3.9600.20044
- Microsoft Windows Server 2012 (Server Core installation): affected >= 6.2.0 and < 6.2.9200.23372
- Microsoft Windows Server 2016: affected >= 10.0.0 and < 10.0.14393.4467
- Microsoft Windows Server 2016 (Server Core installation): affected >= 10.0.0 and < 10.0.14393.4467
- Microsoft Windows Server 2019: affected >= 10.0.0 and < 10.0.17763.1999
- Microsoft Windows Server 2019 (Server Core installation): affected >= 10.0.0 and < 10.0.17763.1999
- Microsoft Windows Server version 2004: affected >= 10.0.0 and < 10.0.19041.1052
- Microsoft Windows Server version 20H2: affected >= 10.0.0 and < 10.0.19042.1052

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31956
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31956

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.