Microsoft SharePoint Improper Authentication Vulnerability

CISA Description

Microsoft SharePoint contains an improper authentication vulnerability that allows an authorized attacker to perform spoofing over a network. Successfully exploitation could allow an attacker to view sensitive information and make some changes to disclosed information. This vulnerability could be chained with CVE-2025-49704. CVE-2025-53771 is a patch bypass for CVE-2025-49706, and the updates for CVE-2025-53771 include more robust protection than those for CVE-2025-49706.

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-2025-49706 ; https://nvd.nist.gov/vuln/detail/CVE-2025-49706