Missing Authentication for Critical Function
Apache ActiveMQ uses LocateRegistry.createRegistry() to create the JMX RMI registry and binds the server to the "jmxrmi" entry. It is possible to connect to the registry without authentication and call the rebind method to rebind jmxrmi to something else. If an attacker creates another server to proxy the original, and bound that, he effectively becomes a man in the middle and is able to intercept the credentials when an user connects. Upgrade to Apache ActiveMQ 5.15.12.
CWE-306 - Missing Authentication for Critical Function
The software does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.