CVE-2026-52869 MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol MCP. Prior to 1.27.2, the SSE and stateful Streamable HTTP transports mcp.server.sse.SseServerTransport and mcp.server.streamablehttpmanager.StreamableHTTPSessionManager route requests to existing...