CVE-2021-31956VulnerabilityPublished 11/03/2021Updated 10/24/2026

CVE-2021-31956: Microsoft Windows NTFS Privilege Escalation Vulnerability

Affects Microsoft WindowsSource CISA KEV

Severity

High

No CVSS score published yet

Exploitation: Actively exploited – in CISA KEV since 11/03/2021
KEV deadline: 11/17/2021
EPSS: 22.3% chance of exploitation in 30 days – higher than 97% of CVEs

What to do

CISA required action

Apply updates per vendor instructions.

nvd.nist.gov/vuln/detail/CVE-2021-31956 (opens in a new tab)

Description

CVE-2021-31956 is a high-severity vulnerability in Microsoft Windows NTFS that allows attackers to escalate privileges by leveraging a specially crafted application. It has been exploited in the wild. No specific affected versions or patch information is provided in the available data.

Summary

Microsoft Windows NTFS contains an unspecified vulnerability (CVE-2021-31956) that enables privilege escalation through a specially crafted application. The vulnerability is classified under CWE-191 (Integer Underflow) and CWE-787 (Out-of-bounds Write). It has been reported as exploited in the wild, indicating active use by attackers. However, no detailed technical specifics or affected Windows versions are provided in the source data.

Impact

Successful exploitation of this vulnerability allows an attacker to escalate privileges on a Windows system, potentially gaining higher-level access than intended. This can lead to unauthorized actions and compromise of system integrity. The presence of known exploitation in the wild increases the urgency of addressing this issue.

Mitigation

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch or official fix information is provided, users should monitor Microsoft security advisories for updates and apply any available patches promptly once released.

CVE-2021-31956: Microsoft Windows NTFS Privilege Escalation Vulnerability

What to do

Description

Summary

Impact

Mitigation

Weaknesses

References

What to do

Description

AnalysisAI-generated, updated 10/24/2026, 09:19:43 UTC

Weaknesses

References

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