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OpenAdvisories
High · 7.4 CVE-2025-69196 EUVD-2025-208759GHSA-5h2m-4q8j-pqpjPYSEC-2026-2474

FastMCP OAuth Proxy token reuse across MCP servers

Published Mar 16, 2026 · Updated Jul 15, 2026 · Assigned by GitHub_M

Description

FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for the base_url passed to the OAuthProxy during initialization. This issue has been patched 2.14.2.

Affected products

VendorProductAffectedFixed
jlowin fastmcp < 2.14.2 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI fastmcp < 2.14.2 2.14.2 GHSA-5h2m-4q8j-pqpj

References