CVE-2026-40466 PoC — Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Possible bypass of CVE-2026-34197 via HTTP discovery secon

Title:Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Possible bypass of CVE-2026-34197 via HTTP discovery second-stage URI (CVE-2026-40466)
Description:Improper Input Validation, Improper Control of Generation of Code ('Code Injection') vulnerability in Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ. An authenticated attacker may bypass the fix in CVE-2026-34197 by adding a connector using an HTTP Discovery transport via BrokerView.addNetworkConnector or BrokerView.addConnector through Jolokia if the activemq-http module is on the classpath. A malicious HTTP endpoint can return a VM transport through the HTTP URI which will bypass the validation added in CVE-2026-34197. The attacker can then use the VM transport's brokerConfig parameter to load a remote Spring XML application context using ResourceXmlApplicationContext. Because Spring's ResourceXmlApplicationContext instantiates all singleton beans before the BrokerService validates the configuration, arbitrary code execution occurs on the broker's JVM through bean factory methods such as Runtime.exec(). This issue affects Apache ActiveMQ Broker: before 5.19.6, from 6.0.0 before 6.2.5; Apache ActiveMQ All: before 5.19.6, from 6.0.0 before 6.2.5; Apache ActiveMQ: before 5.19.6, from 6.0.0 before 6.2.5. Users are recommended to upgrade to version 5.19.6 or 6.2.5, which fixes the issue.

Apache ActiveMQ before 5.19.6 and 6.0.0 through 6.2.4 is vulnerable to remote code execution via a bypass of the CVE-2026-34197 security fix. The original fix blocked the "vm://" transport scheme in BrokerView.addNetworkConnector() and BrokerView.addConnector() to prevent authenticated attackers from loading malicious Spring XML configurations via the Jolokia API. However, the fix only denied the "vm" scheme. An attacker can bypass this restriction by using the HTTP Discovery transport(http://attacker/discovery), which is not in the denied scheme list. The attacker-controlled HTTP endpoint returns a vm:// transport URI as a second-stage response, which then loads a remote Spring XML application context, leading to arbitrary code execution on the broker JVM. The activemq-http module must be on the classpath (present by default in the "all" distribution), and authenticated access to the Jolokia API (/api/jolokia/) is required.

 id: CVE-2026-40466

info:
  name: Apache ActiveMQ - Remote Code Execution via HTTP Discovery Transpo

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