Bug 2457275 (CVE-2026-39304) - CVE-2026-39304 Apache ActiveMQ Client: Apache ActiveMQ Broker: Apache ActiveMQ: Apache ActiveMQ: Denial of Service due to TLSv1.3 KeyUpdate memory exhaustion
Summary: CVE-2026-39304 Apache ActiveMQ Client: Apache ActiveMQ Broker: Apache ActiveM...
Keywords:
Status: NEW
Alias: CVE-2026-39304
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2457420
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-10 11:01 UTC by OSIDB Bzimport
Modified: 2026-04-10 19:51 UTC (History)
31 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-04-10 11:01:21 UTC 
Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ.

ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS.

Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well.
This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4.

Users are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.
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