PyPI/fastmcp CVE-2025-62800: medium 6.1, EPSS 0.28%

FastMCP vulnerable to reflected XSS in client's callback page

Action: Upgrade fastmcp to 2.13.0 or later.

pip install fastmcp==2.13.0

Affected

Fixed versions

Sources

• osv: GHSA-mxxr-jv3v-6pgc
• nvd: CVE-2025-62800
• https://github.com/jlowin/fastmcp/security/advisories/GHSA-mxxr-jv3v-6pgc
• https://github.com/jlowin/fastmcp/pull/2090
• https://github.com/jlowin/fastmcp/commit/2a20f54617a37213ed83894a8c2f0ac38a2e83a3
• https://github.com/jlowin/fastmcp

CVE-2025-62800 · published 2025-10-29T15:38:29Z · modified 2026-07-07T17:56:05.411756133Z · JSON