Apache ActiveMQ DoS via OOM from Uncleaned Rejected Subs (6.3.3,5.19.12)
CVE-2026-108949 Published on November 4, 2026
Apache ActiveMQ, ActiveMQ Broker: Repeated rejected temporary destination consumer requests can lead to broker OOM
Denial of Service via OOM vulnerability in Apache ActiveMQ, ActiveMQ Broker.
An authenticated OpenWire client that sends a ConsumerInfo for a temporary queue/topic owned by another connection is rejected with InvalidDestinationException, but the rejected Subscription is left behind in the region's subscriptions map. Repeating the request leaks broker heap until OOM because the broker does not clean up the rejected subscriptions in the map.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.3.3, before 5.19.12; ActiveMQ Broker: 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.
Weakness Type
What is a Memory Leak Vulnerability?
The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is often triggered by improper handling of malformed data or unexpectedly interrupted sessions. In some languages, developers are responsible for tracking memory allocation and releasing the memory. If there are no more pointers or references to the memory, then it can no longer be tracked and identified for release.
CVE-2026-108949 has been classified to as a Memory Leak vulnerability or weakness.
Products Associated with CVE-2026-108949
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Affected Versions
Apache Software Foundation Apache ActiveMQ:- Version 6.0.0 and below 6.3.3 is affected.
- Before 5.19.12 is affected.
- Version 6.0.0 and below 6.3.3 is affected.
- Before 5.19.12 is affected.