CVE-2025-53770Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

BOD 26-04 remediation window

With CISA's SSVC answers for this CVE (automatable: yes, technical impact: total), BOD 26-04 Table 1 gives 3 days and forensic triage on a publicly exposed asset (row 1) and 3 days and forensic triage on an asset that is not publicly exposed (row 9) ^S06. The catalogue due date, 1 days after the date added, was set before BOD 26-04 took effect on 10 June 2026 ^S06. The directive binds US federal civilian executive branch agencies only.

What CISA says

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.

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

CWE in the catalogue

CWE-502

Official links

• CISA KEV catalogue entry cisa.gov
• NVD record nvd.nist.gov

Vendor advisory and patch links

References NVD tags Vendor Advisory or Patch, exactly as NVD lists them.

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 Vendor Advisory
• https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/ Mitigation, Vendor Advisory

Links in CISA's notes

• 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

NVD details

CWE (NVD)

CWE-502 by secure@microsoft.com

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS versions in NVD

V31

Last modified in NVD

2026-08-04T05:16:34.887

Where each value comes from

This product uses data from the NVD API but is not endorsed or certified by the NVD. CISA does not endorse Sysprobs. Methodology.