Vulnerability Details CVE-2025-53770
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.87
EPSS Ranking 99.4%
CVSS Severity
CVSS v3 Score 9.8
Proposed Action
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.
Ransomware Campaign
Known
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770
- https://arstechnica.com/security/2025/07/sharepoint-vulnerability-with-9-8-severity-rating-is-under-exploit-across-the-globe/
- https://github.com/kaizensecurity/CVE-2025-53770
- https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/
- https://news.ycombinator.com/item?id=44629710
- https://research.eye.security/sharepoint-under-siege/
- https://therecord.media/microsoft-sharepoint-zero-day-vulnerability-exploited-globally
- https://www.bleepingcomputer.com/news/microsoft/microsoft-sharepoint-zero-day-exploited-in-rce-attacks-no-patch-available/
- https://www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770
- https://www.darkreading.com/remote-workforce/microsoft-rushes-emergency-fix-exploited-sharepoint-toolshell-flaw
- https://www.forbes.com/sites/daveywinder/2025/07/20/microsoft-confirms-ongoing-mass-sharepoint-attack---no-patch-available/
- https://x.com/Shadowserver/status/1946900837306868163
Products affected by CVE-2025-53770
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cpe:2.3:a:microsoft:sharepoint_server:-
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cpe:2.3:a:microsoft:sharepoint_server:16.0.17328.20246
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cpe:2.3:a:microsoft:sharepoint_server:16.0.17328.20292
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cpe:2.3:a:microsoft:sharepoint_server:16.0.17328.20362
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cpe:2.3:a:microsoft:sharepoint_server:16.0.17928.20356
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cpe:2.3:a:microsoft:sharepoint_server:16.0.17928.20396
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cpe:2.3:a:microsoft:sharepoint_server:2016
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cpe:2.3:a:microsoft:sharepoint_server:2019