PraisonAI before 4.6.78 contains an authentication bypass in the Call API agent invocation endpoints (src/praisonai/praisonai/api/agent_invoke.py) when PRAISONAI_CALL_AUTH=disabled is configured. The safeguard intended to restrict the disabled-auth opt-out to localhost binding derives the bind host from request.url.hostname, which is taken from the client-controlled HTTP Host header. A remote, unauthenticated attacker who can reach the service over the network can send a spoofed 'Host: 127.0.0.1' header to bypass the localhost-only restriction and list (GET /api/v1/agents) and invoke (POST /api/v1/agents/{agent_id}/invoke) registered agents without authentication.