CVE-2021-27065

Microsoft Exchange Server vulnerabilities (ProxyLogon) enabled widespread remote code execution, actively exploited by ransomware groups.

A critical vulnerability in Microsoft Exchange Server, part of the ProxyLogon exploit chain, allowed for remote code execution, leading to widespread compromise and ransomware attacks. DIB organizations using vulnerable Exchange Server instances face significant exposure, potential compliance failures (CMMC DF, MP), and must immediately patch or mitigate the risk. Failure to address this promptly can result in severe data breaches and regulatory penalties.

Shame score — The widespread exploitation of a known, critical vulnerability in a widely-used enterprise product demonstrates a significant failure in Microsoft's secure development practices and resulted in substantial real-world damage.