Improper invalidation of cached authorizations vulnerability in Apache ActiveMQ, Apache ActiveMQ Runtime Config. After the runtime configuration plugin removes a principal's write grant on a destination, an authenticated connection opened before the change can keep sending to that destination, including through a new anonymous producer, while fresh connections and new explicit producers are denied. This issue affects Apache ActiveMQ: from 6.0.0 before 6.3.3, before 5.19.12; Apache ActiveMQ Runtime Config: from 6.0.0 before 6.3.3, before 5.19.12. Users are recommended to upgrade to version 6.4.0, 6.3.3 or 5.19.12, which fixes the issue.