Severity: important Affected versions:
- Apache ActiveMQ 6.0.0 before 6.3.3 - Apache ActiveMQ before 5.19.12 - Apache ActiveMQ KahaDB 6.0.0 before 6.3.3 - Apache ActiveMQ KahaDB before 5.19.12 Description: Improper input validation vulnerability in Apache ActiveMQ, Apache ActiveMQ KahaDB. A user can create a durable subscription with a clientId and subscription name that have a combined length > 65,535 (while separately being shorter) on a broker using KahaDB which can cause the broker to shutdown and be unrecoverable. This issue affects Apache ActiveMQ: from 6.0.0 before 6.3.3, before 5.19.12; Apache ActiveMQ KahaDB: 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. References: https://activemq.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-111821
