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.
Actively exploited
- In the CISA exploited-vulnerabilities catalogue since Jul 20, 2025
- US federal agencies must remediate it by Jul 21, 2025 (BOD 22-01)
- Attacked 2 days before the vulnerability was made public
- Confirmed by sensors, not only by reports
- Used in ransomware campaigns
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.
Source: CISA KEV · Oct 1, 2026 Sep 26, 2026 Sep 21, 2026 Sep 16, 2026 Sep 13, 2026 Sep 12, 2026
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
| Vendors | Product | Versions |
|---|---|---|
| microsoft | sharepoint server | < 16.0.18526.20508 |
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