ACTIVELY EXPLOITED

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

Facts
VendorMicrosoft
ProductWindows
Actively exploitedYes
Added to CISA KEV3 Nov 2021
CISA federal deadline17 Nov 2021
Weakness (CWE)CWE-191, CWE-787

Required action (CISA's text)

Apply updates per vendor instructions.

Description (NVD)

Microsoft Windows New Technology File System (NTFS) contains an unspecified vulnerability that allows attackers to escalate privileges via a specially crafted application.

SOURCES

Other Microsoft flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.