Fresh SharePoint Vulnerability Exploited Soon After Disclosure

A critical remote code execution vulnerability in Microsoft SharePoint, tracked as CVE-2026-58644, has been actively exploited just days after its disclosure. The flaw, rated with a CVSS score of 9.8, allows authenticated attackers with Site Owner privileges to inject and execute arbitrary code on affected servers. Microsoft addressed the issue during its July 2026 Patch Tuesday release. CISA has added the vulnerability to its Known Exploited Vulnerabilities catalog, urging immediate patching for SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016.