Vulnerability · Published Apr 10, 2026 · Assigned by apache
CVE-2026-39304Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Incorrect handling of TLSv1.3 KeyUpdate can be exploited to cause DoS via OOM
High 7.5
In plain English
A high-severity uncontrolled resource consumption in Apache ActiveMQ from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 60% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | activemq | no fix listed | DEBIAN-CVE-2026-39304 |
| Debian:13 | activemq | no fix listed | DEBIAN-CVE-2026-39304 |
| Maven | org.apache.activemq:activemq-all | 5.19.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:activemq-all | 6.2.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:activemq-broker | 5.19.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:activemq-broker | 6.2.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:activemq-client | 5.19.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:activemq-client | 6.2.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:apache-activemq | 6.2.4 | GHSA-5568-6qcg-g7fx |
| Maven | org.apache.activemq:apache-activemq | 5.19.4 | GHSA-5568-6qcg-g7fx |
| Ubuntu:24.04:LTS | activemq | no fix listed | UBUNTU-CVE-2026-39304 |
| Ubuntu:25.10 | activemq | no fix listed | UBUNTU-CVE-2026-39304 |
| Ubuntu:26.04:LTS | activemq | no fix listed | UBUNTU-CVE-2026-39304 |
| Ubuntu:26.10 | activemq | no fix listed | UBUNTU-CVE-2026-39304 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache ActiveMQ Client | 0 – before 5.19.46.0.0 – before 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ Broker | 0 – before 5.19.46.0.0 – before 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ All | 0 – before 5.19.46.0.0 – before 6.2.4 |
| Apache Software Foundation | Apache ActiveMQ | 0 – before 5.19.46.0.0 – before 6.2.4 |
Weakness: CWE-400, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt vendor-advisory
- http://www.openwall.com/lists/oss-security/2026/04/09/17
- https://access.redhat.com/security/cve/CVE-2026-39304 vdb-entry, x_refsource_REDHAT
- RHBZ#2457275 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-39304.json x_sadp-csaf-vex