Home / Vulnerabilities / CVE-2025-53770
CRITICAL SEVERITY Ransomware Linked
CVE-2025-53770 Microsoft · SharePoint

Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Critical Threat Advisory: This vulnerability is documented in active Ransomware campaigns. Immediate remediation required.

Technical Severity

CVSS v3.1 Metrics

CRITICAL
9.8 / 10
Minimal Risk Critical
Vector Specification
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
Exploitation Likelihood

EPSS Prediction

89.20 %
Predictive Probability
Percentile Rank
99.5 th

Documented as more likely to be exploited than 99.5% of known CVEs.

Detection Date

Jul 20, 2025

Remediation Due

Jul 21, 2025

CISA Catalog Active

Threat Analysis

Microsoft SharePoint Server on-premises contains a deserialization of untrusted data vulnerability that could allow an unauthorized attacker to execute code over a network. This vulnerability could be chained with CVE-2025-53771. CVE-2025-53770 is a patch bypass for CVE-2025-49704, and the updates for CVE-2025-53770 include more robust protection than those for CVE-2025-49704.

Remediation Directive

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.

External Intelligence

CISA

CISA Advisory

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://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://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770
NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2025-53770