Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apache | Activemq | < 5.19.4 |
| Apache | Activemq Broker | < 5.19.4 |
Related Weaknesses (CWE)
References
- https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcementVendor Advisory
- http://www.openwall.com/lists/oss-security/2026/04/09/17Mailing ListThird Party Advisory
FAQ
What is CVE-2026-39304?
CVE-2026-39304 is a vulnerability with a CVSS score of 7.5 (HIGH). 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 ...
How severe is CVE-2026-39304?
CVE-2026-39304 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39304?
Check the references section above for vendor advisories and patch information. Affected products include: Apache Activemq, Apache Activemq Broker.