CVE-2026-33227 Apache ActiveMQ: Improper validation and restriction of a classpath path name

What is CVE-2026-33227?

CVE-2026-33227 is a medium-severity path traversal vulnerability in Apache Activemq, published on 7 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Improper validation and restriction of a classpath path name vulnerability in

Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ Web, Apache ActiveMQ.

In two instances (when creating a Stomp consumer and also browsing messages in the Web console) an authenticated user provided "key" value could be constructed to traverse the classpath due to path concatenation. As a result, the application is exposed to a classpath path resource loading vulnerability that could potentially be chained together with another attack to lead to exploit.

This issue affects Apache ActiveMQ Client: before 5.19.3, from 6.0.0 before 6.2.2; Apache ActiveMQ Broker: before 5.19.3, from 6.0.0 before 6.2.2; Apache ActiveMQ All: before 5.19.3, from 6.0.0 before 6.2.2; Apache ActiveMQ Web: before 5.19.3, from 6.0.0 before 6.2.2; Apache ActiveMQ: before 5.19.3, from 6.0.0 before 6.2.2.

Users are recommended to upgrade to version 5.19.4 or 6.2.3, which fixes the issue. Note: 5.19.3 and 6.2.2 also fix this issue, but that is limited to non-Windows environments due to a path separator resolution bug fixed in 5.19.4 and 6.2.3.

Weakness: CWE-22

Which versions are affected by CVE-2026-33227?

17 open source packages ship an affected version, including org.apache.activemq:activemq-all, activemq and org.apache.activemq:activemq-broker. It affects 3 products.

Products include Apache Activemq, Apache Activemq Broker, Apache Activemq Web.

How do I fix CVE-2026-33227?

Upgrade org.apache.activemq:activemq-all to a fixed version for your release line: 5.19.3 or 6.2.2.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2026-33227 being exploited?

There is no known exploitation of CVE-2026-33227 in the wild and no public exploit code.

Other vulnerabilities in Apache Activemq

• CVE-2023-46604 Apache ActiveMQ Deserialization of Untrusted Data Exploited Critical 10.0
• CVE-2016-3088 Apache ActiveMQ Improper Input Validation Exploited Critical 9.8
• CVE-2026-34197 Apache ActiveMQ Improper Input Validation Exploited High 8.8
• CVE-2020-11998 Remote code execution in Apache ActiveMQ Critical 9.8
• CVE-2013-7285 Command Injection in Xstream Critical 9.8

All Apache Activemq vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-activemq-2026-33227, DEBIAN-CVE-2026-33227, GHSA-h2h4-5m64-m273, MINI-9xg2-hrr3-5rq4, MINI-qg4w-8j9r-2m57, MINI-qxx3-8vj9-gq6v and 5 more.