CISA Urges SharePoint Hardening After New Exploitations

Update July 16, 2026 : CISA has updated this Alert to reflect the addition of CVE-2026-58644 to its Known Exploited Vulnerabilities (KEV) Catalog on July 16, 2026. CISA is aware of active exploitation of vulnerabilities CVE-2026-32201 , CVE-2026-45659 , CVE-2026-56164 , and CVE-2026-58644 , enabling cyber threat actors to gain unauthorized access to on-premises SharePoint Server instances. These vulnerabilities affect all supported on-premises SharePoint Server versions (Subscription Edition, 2019, and 2016) and involve establishing remote code execution (RCE) and post-exploitation activities,