CVE-2026-55531: PraisonAI MCP HTTP server has unauthenticated unbounded session accumulation (memory exhaustion; session TTL never enforced)

The PraisonAI MCP HTTP-stream server creates a new in-memory session on every initialize request and never removes it. The cleanup routine that would expire sessions (_cleanup_sessions) is defined but never called anywhere in the codebase, and the configured session TTL is never enforced. There is no cap on the number of sessions. Because initialize requires no authentication and the server keeps every session dictionary forever, an attacker who can reach the endpoint (directly when the server is bound to a routable address, or from a victim’s browser via the separate Origin-validation bypass) can drive memory usage up without bound until the process is killed by the out-of-memory killer. The same unbounded-growth pattern also applies to the cancelled-requests set populated by notifications/cancelled.