MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection

Summary MCP::Server::Transports::StreamableHTTPTransport the Rack-mountable Streamable HTTP transport in the mcp gem processes every incoming JSON-RPC request without ever inspecting the HTTP Host or Origin request headers. There is no AllowedHosts/AllowedOrigins allowlist and no DNS-rebinding...

CVE-2026-9595

Impact: When a user-configured proxy on webpack-dev-server has a broad context e.g. / and ws: true, it also intercepts the dev server's own HMR WebSocket and forwards it to the proxy target. This leaks the browser's cookies and Origin header to the backend, bypasses the dev server's Host/Origin...

PT-2026-49244

Name of the Vulnerable Software and Affected Versions webpack-dev-server versions prior to 5.2.5 Description A permissive user-configured proxy with a broad context e.g., '/' and ws: true intercepts the development server's own Hot Module Replacement HMR WebSocket and forwards it to the proxy...