High 7.8Known exploited (CISA KEV)Published Jun 8, 2021

CVE-2021-31956Windows NTFS Elevation of Privilege Vulnerability

Updated under an hour ago (Oct 29, 2026, 12:23 AM ET)

Does this affect you?

It affects Microsoft Windows 10 Version 1809 and 18 other products. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021. Treat that date as your deadline.

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Every CVE for Microsoft Windows 10 Version 1809

Exploited in the last 30 days

Windows NTFS Elevation of Privilege Vulnerability

CVSS: 7.8 HIGH (v3.1, CNA)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
Weakness (CWE): CWE-191
Known exploited: Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 22.27% (percentile 98)
Assigned by: microsoft
NVD analysis: Analyzed
Record last updated: Jan 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Microsoft Windows 10 Version 1809 microsoft:windows_10_1809	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows Server 2019 microsoft:windows_server_2019	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows 10 Version 1909 microsoft:windows_10_1909	from 10.0.0 before 10.0.18363.1621	CNA record
Microsoft Windows 10 Version 21H1 microsoft:windows_10_21h1	from 10.0.0 before 10.0.19043.1052	CNA record
Microsoft Windows Server version 2004 microsoft:windows_server_2004	from 10.0.0 before 10.0.19041.1052	CNA record
Microsoft Windows 10 Version 20H2 microsoft:windows_10_20h2	from 10.0.0 before 10.0.19042.1052	CNA record
Microsoft Windows Server version 20H2 microsoft:windows_server_20h2	from 10.0.0 before 10.0.19042.1052	CNA record
Microsoft Windows 10 Version 1507 microsoft:windows_10_1507	from 10.0.0 before 10.0.10240.18967	CNA record
Microsoft Windows 10 Version 1607 microsoft:windows_10_1607	from 10.0.0 before 10.0.14393.4467	CNA record
Microsoft Windows Server 2016 microsoft:windows_server_2016	from 10.0.0 before 10.0.14393.4467	CNA record
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References

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31956	x-refsource-misc, patch, vendor-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31956	us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.