CVE-2021-1647: 
Microsoft System Center Endpoint Protection vulnerability analysis and mitigation

Microsoft Defender experienced a critical Remote Code Execution (RCE) vulnerability, identified as CVE-2021-1647, which was discovered and disclosed in December 2020. The vulnerability affected Microsoft Defender, Microsoft's built-in antimalware solution, and was actively exploited in the wild before patches were released (CISA Alert, CVE MITRE).

The vulnerability was classified as a Remote Code Execution (RCE) flaw in Microsoft Defender that could allow attackers to execute arbitrary code on affected systems. The vulnerability was assigned CVE-2021-1647 and was documented in Microsoft's security advisory system (CVE MITRE).

If successfully exploited, this vulnerability could allow an attacker to take complete control of an affected system, enabling them to execute arbitrary code with elevated privileges (CISA Alert).

Microsoft released security updates to address this vulnerability. CISA encouraged users and administrators to review Microsoft's Advisory and apply the necessary updates to mitigate the risk (CISA Alert).