CERT24Vulnerability in the official Python SDK for MCP could enable OAuth credential theft — 29.09.2026Loading data…
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Vulnerability in the official Python SDK for MCP could enable OAuth credential theft — 29.09.2026

In affected versions of the MCP Python SDK, an MCP server could determine where the client’s OAuth credentials were sent. A malicious or compromised MCP server could therefore receive a client secret, authorization code and PKCE code verifier intended for another authorization server, or a signed client assertion.

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Vulnerability in the official Python SDK for MCP could enable OAuth credential theft — 29.09.2026

In affected versions of the MCP Python SDK, an MCP server could determine where the client’s OAuth credentials were sent. A malicious or compromised MCP server could therefore receive a client secret, authorization code and PKCE code verifier intended for another authorization server, or a signed client assertion.