Microsoft SharePoint Improper Authentication Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2025-07-22
• Known to be used in ransomware campaigns
• EPSS: 99% chance of exploitation in the next 30 days (higher than 100% of CVEs)

[ Description ]Official description

Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

CISA: 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.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 23 Jul 2025): 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.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• msrc.microsoft.com/update-guide/vulnerability/CVE-2025-49706Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource
• www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-p…Press/Media CoverageVendor Advisory