Search: CVE-2025-53770

Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to execute code over a network. Microsoft is aware that an exploit for CVE-2025-53770 exists in the wild. Microsoft is preparing and fully testing a comprehensive update to address this vulnerability. In the meantime, please make sure that the mitigation provided in this CVE documentation is in place so that you are protected from exploitation.

This report discusses open-source intelligence (OSINT) related to disrupting active exploitation of vulnerabilities in on-premises SharePoint deployments. The threat involves multiple advanced persistent threat (APT) groups such as APT31, Emissary Panda, and Storm-2603, leveraging techniques including exploitation of public-facing applications, PowerShell execution, web shells, reflective code loading, and automated data collection. No specific CVE or technical details are provided, and no patch is currently available. The threat is assessed as high severity due to active exploitation and involvement of sophisticated threat actors.