Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
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.
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.
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Details
- Vendor
- Microsoft
- Product
- SharePoint Server
- CVE
- CVE-2025-53770
- Affected versions
- Microsoft SharePoint Enterprise Server 2016 16.0: from 16.0.0 to 16.0.5513.1001 (excluded) — fixed in 16.0.5513.1001
Microsoft SharePoint Server 2019 16.0: from 16.0.0 to 16.0.10417.20037 (excluded) — fixed in 16.0.10417.20037
Microsoft SharePoint Server Subscription Edition 16.0: from 16.0.0 to 16.0.18526.20508 (excluded) — fixed in 16.0.18526.20508 (from the advisory and NVD; check the exact builds in the official advisory) - CVSS score
- 9.8
- Actively exploited
- Yes, listed in the CISA Known Exploited Vulnerabilities catalog
- CISA due date
- July 21, 2025 (deadline for US federal agencies: a good benchmark for you too)
- Source
- CISA KEV – original advisory
- Published
- July 20, 2025
The description and the recommended action are quoted from the public advisory; severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.