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CVE-2025-62800

FastMCP vulnerable to reflected XSS in client's callback page PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
jlowin / fastmcpaffected < 2.13.0

CWE

CWE-79

References

ADP enrichment

CISA-ADP

No English description supplied.