SharePoint RCE CVE-2026-45659 Added to CISA KEV After Active Exploitation

Security professionals have another critical vulnerability to prioritize in their patching queues as CISA has added a Microsoft SharePoint Server remote code execution flaw to its Known Exploited Vulnerabilities catalog. The addition of CVE-2026-45659 to the KEV list comes with concerning confirmation that attackers are actively exploiting this vulnerability in the wild, raising the urgency for organizations using the affected platform.

The vulnerability, which carries a CVSS score of 8.8, represents a significant threat to organizations relying on Microsoft SharePoint Server for collaboration and document management. The technical root cause involves improper handling of deserialization of untrusted data, creating an opening that could allow malicious actors to execute arbitrary code on affected systems remotely. This classification places it among the most severe types of vulnerabilities