CVE-2025-53770
Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019, Microsoft SharePoint Server Subscription Edition
Published 20 Jul 2025 · updated 4 Aug 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 20 Jul 2025, with a remediation deadline of 21 Jul 2025 for US federal agencies. It has been used in ransomware campaigns.
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.
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.
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 · Vendor Advisory
- arstechnica.com/security/2025/07/sharepoint-vulnerability-with-9-8-severity-rating-is-under-exploit-across-the-globe/ · Exploit, Press/Media Coverage
- github.com/kaizensecurity/CVE-2025-53770 · Exploit
- msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/ · Mitigation, Vendor Advisory
- news.ycombinator.com/item?id=44629710 · Issue Tracking
- research.eye.security/sharepoint-under-siege/ · Exploit, Mitigation, Third Party Advisory
- therecord.media/microsoft-sharepoint-zero-day-vulnerability-exploited-globally · Press/Media Coverage
- www.bleepingcomputer.com/news/microsoft/microsoft-sharepoint-zero-day-exploited-in-rce-attacks-no-patch-available/ · Press/Media Coverage
- www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770 · Mailing List, Third Party Advisory, US Government Resource
- www.darkreading.com/remote-workforce/microsoft-rushes-emergency-fix-exploited-sharepoint-toolshell-flaw · Press/Media Coverage
- www.forbes.com/sites/daveywinder/2025/07/20/microsoft-confirms-ongoing-mass-sharepoint-attack---no-patch-available/ · Press/Media Coverage
- x.com/Shadowserver/status/1946900837306868163 · Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53770 · US Government Resource