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CISA Known Exploited Vulnerabilities

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV
2025-07-20
Remediation due
2025-07-21
Ransomware
Known use

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 notes
CISA Mitigation Instructions: https://www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770; https://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/ ; https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 ; https://nvd.nist.gov/vuln/detail/CVE-2025-53770

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.

Severity

CVSS 3.1 · CNA9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:W/RC:C
SSVC · CISA-ADP
Exploitationactive
Automatableyes
Technical impacttotal

Affected Products

VendorProductAffected versions
MicrosoftMicrosoft SharePoint Enterprise Server 2016
16.0.0 to <16.0.5513.1001
MicrosoftMicrosoft SharePoint Server 2019
16.0.0 to <16.0.10417.20037
MicrosoftMicrosoft SharePoint Server Subscription Edition
16.0.0 to <16.0.18526.20508

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.