CISA: Microsoft SharePoint RCE flaw now actively exploited

The U.S. Cybersecurity and Infrastructure Security Agency added CVE-2026-45659, a high-severity remote code execution flaw in Microsoft SharePoint Server, to its Known Exploited Vulnerabilities catalog on Wednesday. Attackers exploit this deserialization weakness without admin privileges or user interaction. Federal Civilian Executive Branch agencies must patch by July 4, 2026.