CVEs / CVE-2025-53770
CVE-2025-53770: Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
- Known exploited in the CISA KEV catalog since 20 Jul 2025
- critical 9.8 CVSS 3.1 (from the CNA)
- EPSS 99.9% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Microsoft SharePoint Enterprise Server 2016 | from 16.0.0, before 16.0.5513.1001 | 16.0.5513.1001 |
| Microsoft Microsoft SharePoint Server 2019 | from 16.0.0, before 16.0.10417.20037 | 16.0.10417.20037 |
| Microsoft Microsoft SharePoint Server Subscription Edition | from 16.0.0, before 16.0.18526.20508 | 16.0.18526.20508 |
Exploitation
| In CISA KEV since | 20 Jul 2025 |
|---|---|
| Due date for US federal agencies | 21 Jul 2025 |
| Used in ransomware campaigns | Known |
| 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. |
Severity
| CVSS 3.1 | 9.8 criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-502 |
References
- CVE-2025-53770 on NVD
- CVE-2025-53770 in the CISA KEV catalog
- https://www.cisa.gov/news-events/alerts/2025/07/20/microsoft-releases-guidance-exploitation-sharepoint-vulnerability-cve-2025-53770 (cited by CISA)
- https://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/ (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770 Vendor Advisory
- https://arstechnica.com/security/2025/07/sharepoint-vulnerability-with-9-8-severity-rating-is-under-exploit-across-the-globe/ Exploit, Press/Media Coverage
- https://github.com/kaizensecurity/CVE-2025-53770 Exploit
- https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/ Mitigation, Vendor Advisory
- https://news.ycombinator.com/item?id=44629710 Issue Tracking
- https://research.eye.security/sharepoint-under-siege/ Exploit, Mitigation, Third Party Advisory
- https://therecord.media/microsoft-sharepoint-zero-day-vulnerability-exploited-globally Press/Media Coverage
- https://www.bleepingcomputer.com/news/microsoft/microsoft-sharepoint-zero-day-exploited-in-rce-attacks-no-patch-available/ Press/Media Coverage
- https://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
- https://www.darkreading.com/remote-workforce/microsoft-rushes-emergency-fix-exploited-sharepoint-toolshell-flaw Press/Media Coverage
- https://www.forbes.com/sites/daveywinder/2025/07/20/microsoft-confirms-ongoing-mass-sharepoint-attack---no-patch-available/ Press/Media Coverage
- https://x.com/Shadowserver/status/1946900837306868163 Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-53770 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.