Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.
Microsoft · SharePoint Server
Known ransomware use: Unknown
Follow the source advisory and validate exposure in your environment.
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Recent reporting that mentions CVE-2026-45659.
On July 2, 2026, CISA added CVE-2026-45659, a SharePoint Server RCE, to its Known Exploited Vulnerabilities catalog with a two-day patch deadline. Storm-2603 is using it to stage Warlock ransomware, living off the land the whole way. Here is why it matters, plus a free 12-rule Sigma pack to hunt it.
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Wednesday added a high-severity flaw impacting Microsoft SharePoint Server to its Known Exploited Vulnerabilities (KEV) catalog, citing evidence of active exploitation
A critical vulnerability, tracked as CVE-2026-45659, in Microsoft SharePoint can allow attackers to achieve remote code execution with little effort. Microsoft released security updates to patch a high-severity SharePoint vulnerability, tracked as CVE-2026-45659 (CVSS score of 8.8), that could allow remote code execution. The flaw does not require complex conditions for exploitation, making it a […]
Microsoft has rolled out updates to fix a remote code execution vulnerability impacting SharePoint that could be exploited by bad actors in attacks without requiring any specialized conditions to be met