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CVE-2025-62800
Published: Oct 28, 2025
Modified: Oct 29, 2025
PUBLISHED
Description
FastMCP is the standard framework for building MCP applications. Versions prior to 2.13.0 have a reflected cross-site scripting vulnerability in the OAuth client callback page (oauth_callback.py) where unescaped user-controlled values are inserted into the generated HTML, allowing arbitrary JavaScript execution in the callback server origin. The issue is fixed in version 2.13.0.
| Vendor | Product | Versions |
|---|---|---|
jlowin | fastmcp | affected < 2.13.0 |
Weaknesses (CWE)
References
https://github.com/jlowin/fastmcp/security/advisories/GHSA-mxxr-jv3v-6pgc
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