Summary More methods than expected can be called on reflex instances. Being able to call some of them has security implications. Details To invoke a reflex a websocket message of the following shape is sent: json { "target": "[class_name]#[method_name]", "args": [] } The server will proceed to instantiate reflex using the provided class_name as long as it extends StimulusReflex::Reflex. It then attempts to call method_name on the instance with the provided arguments ref: “`ruby method = reflex.method method_name required_params = method.parameters.select { |(kind, )| kind == :req } optional_params = method.parameters.select { |(kind, )| kind == :opt } if arguments.size >= required_params.size && arguments.size <= required_params.size + optional_params.size reflex.public_send(method_name, *arguments) end “` This is problematic as reflex.method(method_name) can be more methods than those explicitly specified by the developer in their reflex class. A good example is the instance_variable_set method. Read more Let's imagine a reflex that uses `@user` as a trusted variable in an `after_reflex` callback. This variable can be overwritten using the following message: “`json { "target": "ChatReflex#instance_variable_set", "args": ["@user", ""] } “` Here are other interesting methods that were found to be available for the [ChatReflex sample…Read More