CVE-2026-55529 PraisonAI: Origin validation bypass in MCP HTTP Stream transport allows browser-mediated unauthenticated tool execution on local MCP server

PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, the MCP HTTP Stream validateorigin method accepts requestorigin.startswithallowed, so the attacker-controlled localhost.evil.example HTTP origin matches the localhost allowlist. Without an API key, a malicious webpage can submit...

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...

EUVD-2026-50489

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

CVE-2026-63118

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a...

EUVD-2026-21061

Apollo MCP Server is a Model Context Protocol server that exposes GraphQL operations as MCP tools. Prior to version 1.7.0, the Apollo MCP Server did not validate the Host header on incoming HTTP requests when using StreamableHTTP transport. In configurations where an HTTP-based MCP server is run ...

DNS Rebinding

@modelcontextprotocol/sdk is vulnerable to DNS Rebinding. The vulnerability is due to DNS rebinding protection being disabled by default in unauthenticated HTTP-based servers, which allows an attacker to exploit a malicious website to bypass same-origin policy and send requests to the local MCP...