GHSA-5H93-6WHR-6Q8J Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies

Summary In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client for example an X-API-Key credential were sent to that origin, an...

Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies

Summary In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client for example an X-API-Key credential were sent to that origin, an...

CVE-2026-116685

The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamablehttpclient, streamablehttpclient, sseclient, ClientSessionGroup, OAuth, and createmcphttpclient client paths enable followredirects and...