July 20, 2025 · Applied Cybernetics Group
CVE-2025-53770 — Microsoft SharePoint
known ransomware use
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
- Added to KEV
2025-07-20- Federal due date
2025-07-21- Vendor
- Microsoft
- Product
- SharePoint
- EPSS
- 100.0th percentile (score 1.000, as of
2026-07-13) - NVD CVSS v3.1
- 9.8 (CRITICAL)
- Ransomware use
- Known
- ATT&CK
- T1059 , T1190 · signal rollup
- Upstream
- https://nvd.nist.gov/vuln/detail/CVE-2025-53770
CISA short description
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.
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.
NVD 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.