Apache ActiveMQ Excessive Memory Alloc via OpenWire (5.x/6.x)
CVE-2025-27533 Published on May 7, 2025
Apache ActiveMQ: Unchecked buffer length can cause excessive memory allocation
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.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2025-27533 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2025-27533
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Affected Versions
Apache Software Foundation Apache ActiveMQ:- Version 6.0.0 and below 6.1.6 is affected.
- Version 5.18.0 and below 5.18.7 is affected.
- Version 5.17.0 and below 5.17.7 is affected.
- Version 5.16.0 and below 5.16.8 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.