5.3
Medium
CVE-2025-62800 FastMCP is the standard framework for building MCP applications
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| fastmcp 2.13 | earliest → < 2.13.0 | 2.13.0 |
Other CVEs of fastmcp
The 5 CVEs of fastmcp →
CVE-2026-27124
FastMCP is the standard framework for building MCP applications
8.2
High
CVE-2025-64340
FastMCP is the standard framework for building MCP applications
6.7
Medium
CVE-2025-69196
FastMCP is the standard framework for building MCP applications
7.4
High
CVE-2025-62801
FastMCP is the standard framework for building MCP applications
5.4
Medium