Microsoft SharePoint Remote Code Execution Vulnerability
Prioritize patching. It under exploitation confirmed by CISA and has a public proof of concept.
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.
Microsoft SharePoint can be tricked into running malicious code sent over the network because it doesn't properly check data before processing it. This is dangerous because attackers can take complete control of the affected system without needing special access.
The vulnerability exists in SharePoint's deserialization mechanism (CWE-502) which processes untrusted data without validation, allowing remote code execution. An attacker can send malicious serialized objects over the network to achieve code execution with no prior authentication required, resulting in complete system compromise.