ACTIVELY EXPLOITED

CVE-2021-1647: Microsoft Defender Remote Code Execution Vulnerability

Facts
VendorMicrosoft
ProductDefender
Actively exploitedYes
Added to CISA KEV3 Nov 2021
CISA federal deadline17 Nov 2021
Weakness (CWE)CWE-122, CWE-1285

Required action (CISA's text)

Apply updates per vendor instructions.

Description (NVD)

Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.

SOURCES

Other Microsoft flaws

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