CISA Adds Exploited SharePoint RCE Zero-Day CVE-2026-58644 to KEV
In July 2026, Microsoft disclosed CVE-2026-58644, a critical deserialization vulnerability in SharePoint Server, allowing unauthenticated remote code execution. This flaw affects SharePoint Server Subscription Edition, 2019, and Enterprise Server 2016. Exploitation requires an attacker to send a specially crafted network request, leading to potential full server compromise. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added this vulnerability to its Known Exploited Vulnerabilities catalog, mandating federal agencies to apply patches by July 19, 2026. The inclusion of CVE-2026-58644 in CISA's catalog underscores the urgency of addressing this vulnerability, as it has been actively exploited in the wild. Organizations using affected SharePoint versions should prioritize patching to mitigate the risk of unauthorized access and potential data breaches.
Kill Chain