Apache ActiveMQ does not properly validate the remaining length field which may lead to an overflow during the decoding of malformed packets. When this integer overflow occurs, ActiveMQ may incorrectly compute the total Remaining Length and subsequently misinterpret the payload as multiple MQTT control packets which makes the broker susceptible to unexpected behavior when interacting with non-compliant clients. This behavior violates the MQTT v3.1.1 specification, which restricts Remaining Length to a maximum of 4 bytes. The scenario occurs on established connections after the authentication process. Brokers that are not enabling mqtt transport connectors are not impacted.
This issue affects Apache ActiveMQ: before 5.19.2, 6.0.0 to 6.1.8, and 6.2.0
Users are recommended to upgrade to version 5.19.2, 6.1.9, or 6.2.1, which fixes the issue.
| Software | From | Fixed in |
|---|---|---|
org.apache.activemq / apache-activemq
|
- | 5.19.2 |
org.apache.activemq / apache-activemq
|
6.0.0 | 6.1.9 |
org.apache.activemq / apache-activemq
|
6.2.0 | 6.2.0.x |
org.apache.activemq / apache-activemq
|
6.2.0 | 6.2.1 |
org.apache.activemq / activemq-all
|
- | 5.19.2 |
org.apache.activemq / activemq-all
|
6.0.0 | 6.1.9 |
org.apache.activemq / activemq-all
|
6.2.0 | 6.2.0.x |
org.apache.activemq / activemq-all
|
6.2.0 | 6.2.1 |
org.apache.activemq / activemq-mqtt
|
- | 5.19.2 |
org.apache.activemq / activemq-mqtt
|
6.0.0 | 6.1.9 |
org.apache.activemq / activemq-mqtt
|
6.2.0 | 6.2.0.x |
org.apache.activemq / activemq-mqtt
|
6.2.0 | 6.2.1 |
| apache / activemq | - | 5.19.2 |
| apache / activemq | 6.2.0 | 6.2.0.x |
| apache / activemq | 6.0.0 | 6.1.8.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
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