CVE-2026-59950 — MCP Python SDK: WebSocket server transport does not support Host/Origin validation
The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server tra…
Published: 2026-07-15 · CVSS: 7.6 · CVSS 4.0
The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that exposed that transport. This issue is fixed in version 1.28.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7