Successful exploitation of CVE-2025-53770 could expose MachineKey configuration details from a vulnerable SharePoint Server, ultimately enabling unauthenticated remote code execution.

CVE-2025-53770: Frequently Asked Questions About Zero-Day SharePoint Vulnerability Exploitation

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.

Zero-day in Microsoft SharePoint Server is under active exploitation according to multiple firms. No patch available yet. Mitigation instructions available.

The Microsoft SharePoint Server Subscription Edition installation on the remote host is missing security updates. It is, therefore, affected by multiple security vulnerabilities:

  - Improper limitation of a pathname to a restricted directory ('path traversal') in Microsoft     Office SharePoint allows an authorized attacker to perform spoofing over a network. (CVE-2025-53771)

  - Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized     attacker to execute code over a network. (CVE-2025-53770)

The Microsoft SharePoint Server 2019 installation on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

  - Improper limitation of a pathname to a restricted directory ('path traversal') in Microsoft     Office SharePoint allows an authorized attacker to perform spoofing over a network. (CVE-2025-53771)

  - Deserialization of untrusted data in on-premises Microsoft SharePoint Server allows an unauthorized     attacker to execute code over a network. (CVE-2025-53770)

ID	Name	Product	Family	Severity
242415	Security Updates for Microsoft SharePoint Server Subscription Edition (July 2025)	Nessus	Windows : Microsoft Bulletins	critical
242414	Security Updates for Microsoft SharePoint Server 2019	Nessus	Windows : Microsoft Bulletins	critical

Detections

Analytics

CVE-2025-53770

critical

Tenable Plugins

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critical