CVE-2026-27124 in fastmcp

Sumário (Inglês)

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.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Responsável

GitHub_M

Reservar

17/02/2026

Divulgação

03/04/2026

Estado

Confirmado

Inscrições

VulDB provides additional information and datapoints for this CVE:

ID	Vulnerabilidade	CWE	Exp	Con	CVE
355173	jlowin fastmcp Elevação de Privilégios	441	Não definido	Correção oficial	CVE-2026-27124

Fontes

• MITRE
• NVD
• CVE Details