CVE-2025-27533: Apache ActiveMQ: Unchecked buffer length can cause excessive memory allocation

["Christopher L. Shannon" <cshannon () apache org>]

Affected versions:

- Apache ActiveMQ 6.0.0 before 6.1.6
- Apache ActiveMQ 5.18.0 before 5.18.7
- Apache ActiveMQ 5.17.0 before 5.17.7
- Apache ActiveMQ 5.16.0 before 5.16.8

Description:

Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ.

During unmarshalling of OpenWire commands the size value of buffers was not properly validated which could lead to 
excessive memory allocation and be exploited to cause a denial of service (DoS) by depleting process memory, thereby 
affecting applications and services that rely on the availability of the ActiveMQ broker when not using mutual TLS 
connections.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.1.6, from 5.18.0 before 5.18.7, from 5.17.0 before 5.17.7, 
before 5.16.8. ActiveMQ 5.19.0 is not affected.

Users are recommended to upgrade to version 6.1.6+, 5.19.0+,  5.18.7+, 5.17.7, or 5.16.8 or which fixes the issue.

Existing users may implement mutual TLS to mitigate the risk on affected brokers.

This issue is being tracked as AMQ-6596 

References:

https://activemq.apache.org/
https://www.cve.org/CVERecord?id=CVE-2025-27533
https://issues.apache.org/jira/browse/AMQ-6596