cvedb.io
CVE-2026-27124
MEDIUM · CVSS 6.1
EPSS exploitation probability: 0%
Published 2026-04-03T16:16:36.453 · Last modified 2026-06-17T10:26:42.537

Summary

FastMCP is the standard framework for building MCP applications. Prior to version 3.2.0, while testing the GitHubProvider OAuth integration, which allows authentication to a FastMCP MCP server via a FastMCP OAuthProxy using GitHub OAuth, it was discovered that the FastMCP OAuthProxy does not properly validate the user's consent upon receiving the authorization code from GitHub. In combination with GitHub’s behavior of skipping the consent page for previously authorized clients, this introduces a Confused Deputy vulnerability. This issue has been patched in version 3.2.0.

Affected products

jlowin — fastmcp

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.