๐Ÿ” CVE Alert

CVE-2026-39304

HIGH 7.5

Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Incorrect handling of TLSv1.3 KeyUpdate can be exploited to cause DoS via OOM

CVSS Score
7.5
EPSS Score
0.0%
EPSS Percentile
5th

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.

Vendor apache software foundation
Product apache activemq client
Published Apr 10, 2026
Last Updated Apr 10, 2026
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Affected Versions

Apache Software Foundation / Apache ActiveMQ Client
0 < 5.19.4 6.0.0 < 6.2.4
Apache Software Foundation / Apache ActiveMQ Broker
0 < 5.19.4 6.0.0 < 6.2.4
Apache Software Foundation / Apache ActiveMQ All
0 < 5.19.4 6.0.0 < 6.2.4
Apache Software Foundation / Apache ActiveMQ
0 < 5.19.4 6.0.0 < 6.2.4

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
activemq.apache.org: https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt openwall.com: http://www.openwall.com/lists/oss-security/2026/04/09/17