Microsoft Exchange Server Critical Vulnerabilities

**Executive Summary:** Microsoft released critical security updates for four on‑premises Exchange Server RCE vulnerabilities (CVE-2021-28480–28483) affecting Exchange Server 2013/2016/2019; CISA issued an urgent directive to patch federal systems, and Arctic Wolf urges customers to apply patches, deploy monitoring (Arctic Wolf Agent, Sysmon), and prioritize remediation due to the risk that attackers could reverse‑engineer patches to develop exploits despite no confirmed in‑the‑wild exploitation at the time of the report.