Microsoft · SharePoint
CVE-2025-53770
Microsoft SharePoint Server Remote Code Execution Vulnerability
What it is
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.
CISA: 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.
What to do
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.
Deadline for US federal agencies: July 21, 2025
More exploited flaws from Microsoft
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 25, 2026 | Code Injection | SharePoint | High 8.8 | 8.2% |
| Aug 18, 2026 | Weak Authentication | SharePoint | Critical 9.1 | 70% |
| Jul 22, 2026 | Deserialization of Untrusted Data Vulnerability | SharePoint | Critical 9.8 | 3.0% |
| Jul 16, 2026 | Deserialization of Untrusted Data | SharePoint | Critical 9.8 | 16% |
| Mar 18, 2026 | Deserialization of Untrusted Data | SharePoint | Critical 9.8 | 29% |
| Jul 22, 2025 | Code Injection | SharePoint | High 8.8 | >99.9% |
| Jul 22, 2025 | Improper Authentication | SharePoint | Medium 6.5 | 99.1% |
| Oct 22, 2024 | Deserialization | SharePoint | High 7.2 | 51% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.