Microsoft · SharePoint
CVE-2025-53770
Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
CISA KEV record
- CISA date added
- 2025-07-20
- CISA due date
- 2025-07-21
- Known ransomware use
- Known
NVD risk context
9.8 CRITICAL
CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.
Description
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.
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.
NVD reference index
Vendor and remediation references
NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 ↗
- https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/ ↗
- https://research.eye.security/sharepoint-under-siege/ ↗
Other NVD references (10)
- 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://news.ycombinator.com/item?id=44629710 ↗
- 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 ↗
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53770 ↗
MITRE CWE context
CWE classification
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
View official MITRE CWE details ↗NVD record timing
NVD record timeline
These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.
- NVD published
- Jul 20, 2025, 01:15 AM UTC When NVD first published this CVE record.
- NVD last updated
- Jun 17, 2026, 09:38 AM UTC When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector
This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA 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-2025-53770 ; https://nvd.nist.gov/vuln/detail/CVE-2025-53770
- 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-2025-53770
- https://nvd.nist.gov/vuln/detail/CVE-2025-53770