How severe is CVE-2021-31956?

CVE-2021-31956 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-31956 being actively exploited?

Yes. CVE-2021-31956 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-31956?

CVE-2021-31956 primarily affects Microsoft Windows 10 1507. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31956?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-31956 have an EU (EUVD) identifier?

Yes. CVE-2021-31956 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-18829. It is also flagged as exploited in the EUVD (since 2021-11-03).

When was CVE-2021-31956 published?

CVE-2021-31956 was published on 2021-06-08 and last updated on 2026-06-17.

CVE-2021-31956

CVE-2021-31956 is a high-severity vulnerability in Microsoft Windows 10 1507 with a CVSS 3.x base score of 7.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-191.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 9.3
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
EU (EUVD) id: EUVD-2021-18829
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
Weakness: CWE-191
Affected product: Microsoft Windows 10 1507
Published: 2021-06-08
Last modified: 2026-06-17

Description

Windows NTFS Elevation of Privilege Vulnerability

Frequently asked questions

What is CVE-2021-31956?: Windows NTFS Elevation of Privilege Vulnerability
How severe is CVE-2021-31956?: CVE-2021-31956 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-31956 being actively exploited?: Yes. CVE-2021-31956 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-31956?: CVE-2021-31956 primarily affects Microsoft Windows 10 1507. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31956?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-31956 have an EU (EUVD) identifier?: Yes. CVE-2021-31956 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-18829. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2021-31956 published?: CVE-2021-31956 was published on 2021-06-08 and last updated on 2026-06-17.

References

Affected products (18)

cpe:2.3:o:microsoft:windows_10_1507:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_1909:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_2004:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_20h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10_21h1:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_7:-:sp1:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_8.1:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_rt_8.1:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2004:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2008:r2:sp1:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2008:sp2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_20h2:*:*:*:*:*:*:*:*

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