Actively exploited in the wild
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Microsoft - SharePoint · Listed in the CISA KEV since 2025-07-20. This indicates confirmed attacks in production environments.
Required action: Disconnect public-facing versions of SharePoint Server that have reached their end-of-life (EOL) or end-of-service (EOS) to include SharePoint Server 2013 and earlier versions. For supported versions, please follow the mitigations according to CISA (URL listed below in Notes) and vendor instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
CVE-2025-53770
CriticalCVSS 9.8KEVExploitation Probability (EPSS)
Very high risk100th percentile - higher than 100% of all known CVEs
Summary
Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized attacker to execute code over a network. Microsoft is aware of an exploit in the wild and is preparing an update.
Risk Assessment
An attacker can remotely execute code on the SharePoint server, potentially leading to server compromise and data breach. Immediate mitigation is recommended.
Recommendation
Implement mitigations described in the CVE documentation and monitor Microsoft communications for updates.
Original NVD description (English source)
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.