CVE-2026-40466
HighCVSS 8.8Exploitation Probability (EPSS)
Very high risk91th percentile - higher than 91% of all known CVEs
Summary
A vulnerability in Apache ActiveMQ allows an authenticated attacker to bypass the fix for CVE-2026-34197 by adding a connector using HTTP Discovery transport. The attacker can use a malicious HTTP endpoint returning a VM transport, leading to loading a remote Spring XML application context and arbitrary code execution on the broker's JVM.
Risk Assessment
The risk involves remote code execution (RCE) by an authenticated attacker, potentially leading to full compromise of the ActiveMQ broker, impacting confidentiality, integrity, and availability.
Recommendation
It is recommended to upgrade Apache ActiveMQ to version 5.19.6 or 6.2.5, which contain the fix for this vulnerability.
Original NVD description (English source)
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.