A guest mruby script running inside the Kobako sandbox can execute arbitrary Ruby code in the host process, resulting in a complete sandbox escape. The issue occurs because the transport dispatcher passes guest-supplied method names directly to `Object#public send` on bound Service objects without restricting them to the object's own methods. An attacker can use the public `send` method to pivot into private Kernel methods, such as by passing `method = "send"` and `args = [:eval, "<ruby>"]`, which allows the execution of attacker-controlled Ruby code in the host process. This enables the attacker to read or modify host state and spawn processes.