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7.5
Apache ActiveMQ Can Run Out of Memory with Certain TLS Handshakes
CVE-2026-39304
GHSA-5568-6qcg-g7fx
BIT-activemq-2026-39304
Summary
Apache ActiveMQ versions 5.19.4 and earlier, and 6.0.0 to 6.2.3, are vulnerable to a denial of service attack that can cause the software to run out of memory when handling certain types of secure connections. This could lead to the software becoming unresponsive or crashing. To fix this, upgrade to version 6.2.4 or 5.19.5.
What to do
- Update org.apache.activemq:activemq-client to version 5.19.4.
- Update org.apache.activemq:activemq-client to version 6.2.4.
- Update org.apache.activemq:activemq-broker to version 5.19.4.
- Update org.apache.activemq:activemq-broker to version 6.2.4.
- Update org.apache.activemq:activemq-all to version 5.19.4.
- Update org.apache.activemq:activemq-all to version 6.2.4.
- Update org.apache.activemq:apache-activemq to version 5.19.4.
- Update org.apache.activemq:apache-activemq to version 6.2.4.
- Update activemq to version 6.2.4.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| maven | – | org.apache.activemq:activemq-client |
< 5.19.4 >= 6.0.0, < 6.2.4 Fix: upgrade to 5.19.4
|
| maven | – | org.apache.activemq:activemq-broker |
< 5.19.4 >= 6.0.0, < 6.2.4 Fix: upgrade to 5.19.4
|
| maven | – | org.apache.activemq:activemq-all |
< 5.19.4 >= 6.0.0, < 6.2.4 Fix: upgrade to 5.19.4
|
| maven | – | org.apache.activemq:apache-activemq |
< 5.19.4 >= 6.0.0, < 6.2.4 Fix: upgrade to 5.19.4
|
| Bitnami | – | activemq |
>= 6.0.0, < 6.2.4 Fix: upgrade to 6.2.4
|
Original title
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
Original 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.
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.
Vulnerability type
CWE-400
Uncontrolled Resource Consumption
Published: 16 Apr 2026 · Updated: 17 Apr 2026 · First seen: 10 Apr 2026