CVE-2026-58644
Microsoft SharePoint
Summary
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
Published 2026-07-16 · first seen here 2026-10-10
CISA required action (due 2026-07-19): 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.
Exploit availability
Public exploit code lowers the bar for attackers, so prioritise patching and hunting. These repositories are unverified. Fake PoCs that contain malware are common, so never run them outside an isolated lab.
- Nuclei detection template · ProjectDiscovery
Hunt & detect
Threat hunt brief, Sigma rule and Splunk / Sentinel / CrowdStrike queries are not available for this item yet.