CVE-2025-53770

CriticalActively exploited (CISA KEV)Known to be used in ransomware campaigns

Description

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductMicrosoft SharePoint
PublishedJul 20, 2025
First seenJul 20, 2025
Added to KEVJul 20, 2025

How to fix

CISA 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.

CISA due date: Jul 21, 2025
Update
  • microsoft sharepoint_server16.0.18526.20508 or later

Affected products

ProductAffected versionsFixed in
microsoft sharepoint_serverv < 16.0.18526.20508, 2016, 201916.0.18526.20508

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