CVE-2025-62800
FastMCP
- Severity
- Medium
- Published
- October 28, 2025
- Last modified
- October 8, 2026
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.
CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness
- CWE-79 Cross-site scripting
References
- github.comExploitThird Party Advisory
- github.comExploitThird Party Advisory
Listed in
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