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.

Published: Jul 20, 2025
Updated: Jul 22, 2025
CVE: CVE-2025-53770
Severity: Critical
Exploit:

CVSS v3:

Severity: Critical
Score: 9.8
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWEs:

CWE-502

OWASP TOP 10:

A8 - Insecure Deserialization

Affected Software
References

Software	From	Fixed in
microsoft / sharepoint_server	2019	2019.x
microsoft / sharepoint_server	2016	2016.x
microsoft / sharepoint_server	-	16.0.18526.20508

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://msrc.microsoft.com/update-guide/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

Vulnerability Database

CVE-2025-53770