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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache ActiveMQ Client | < 5.19.4; >= 6.0.0, < 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ Broker | < 5.19.4; >= 6.0.0, < 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ All | < 5.19.4; >= 6.0.0, < 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ | < 5.19.4; >= 6.0.0, < 6.2.4 |
| Red Hat | Red Hat AMQ Broker 7 | — |
| Red Hat | Red Hat AMQ Broker 7 | — |
| Red Hat | Red Hat build of Apache Camel for Spring Boot 4 | — |
| Red Hat | Red Hat Data Grid 8 | — |
| Red Hat | Red Hat Data Grid 8 | — |
| Red Hat | Red Hat Enterprise Linux 8 | — |
| Red Hat | Red Hat Enterprise Linux 9 | — |
| Red Hat | Red Hat Fuse 7 | — |
| Red Hat | Red Hat Fuse 7 | — |
| Red Hat | Red Hat Fuse 7 | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | — |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | — |
References
- https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txtVendor Advisory
- http://www.openwall.com/lists/oss-security/2026/04/09/17Mailing List, Third Party Advisory
- https://access.redhat.com/security/cve/CVE-2026-39304
- https://bugzilla.redhat.com/show_bug.cgi?id=2457275
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39304.json
Timeline
- Published
- Apr 10, 2026
- Last modified
- Oct 26, 2026
- NVD status
- Modified