A denial of service vulnerability exists in Apache ActiveMQ Broker where an authenticated OpenWire client can cause an out-of-memory condition by repeatedly sending a ConsumerInfo for a temporary queue or topic owned by another connection. The broker rejects the request but fails to clean up the rejected subscription, leading to heap memory leakage until the broker runs out of memory. This affects Apache ActiveMQ versions from 6.0.0 before 6.3.3 and before 5.19.12. Upgrading to versions 6.4.0, 6.3.3, or 5.19.12 resolves the issue.