CVE-2021-1647
Published: November 3, 2021
Official Description
Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.
CISA KEV Advisory
Microsoft Defender Remote Code Execution Vulnerability
Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.
Apply updates per vendor instructions.
Risk Analysis
This unspecified vulnerability in Microsoft Defender allows for remote code execution. With an EPSS score of 0.77891 and its presence in CISA's KEV, this flaw is highly likely to be exploited and poses a significant risk to systems running Microsoft Defender.
Active exploitation of this vulnerability has been observed in the wild, confirming its critical nature. The flaw is remotely exploitable, indicating a severe and immediate threat.
Administrators should apply the latest security updates for Microsoft Defender. Ensure real-time protection is enabled and regularly scan systems for threats.
Technical Analysis
CVE-2021-1647 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-1647 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-1647 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1