CVE-2026-40466
Published: 24 April 2026
Summary
CVE-2026-40466 is a high-severity Improper Input Validation (CWE-20) vulnerability in Apache Activemq. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 10.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and AC-6 (Least Privilege).
Deeper analysis
CVE-2026-40466 is an improper input validation and code injection vulnerability affecting Apache ActiveMQ Broker, Apache ActiveMQ All, and Apache ActiveMQ. It impacts versions before 5.19.6 and versions from 6.0.0 before 6.2.5. The flaw resides in the broker's handling of network connectors added through management interfaces when the activemq-http module is present on the classpath.
An authenticated attacker with access to Jolokia can exploit the issue by invoking BrokerView.addNetworkConnector or BrokerView.addConnector to register an HTTP Discovery transport. A malicious HTTP endpoint can supply a VM transport URI that evades the validation introduced for CVE-2026-34197; the attacker then supplies a brokerConfig parameter referencing a remote Spring XML context. Because ResourceXmlApplicationContext instantiates beans before BrokerService performs its checks, arbitrary code execution occurs inside the broker JVM via methods such as Runtime.exec().
The Apache ActiveMQ project recommends upgrading to version 5.19.6 or 6.2.5 to resolve the vulnerability. The associated EPSS score has remained flat at 0.1801 with no material increase observed after disclosure.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25410
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability enables remote authenticated attackers to achieve arbitrary code execution via improper input validation and code injection in the Jolokia HTTP interface of Apache ActiveMQ, directly mapping to exploitation of a public-facing application.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces validation of connector URIs, transport parameters, and brokerConfig values supplied via Jolokia to block the HTTP-to-VM bypass and subsequent ResourceXmlApplicationContext loading.
Restricts authenticated Jolokia users from invoking BrokerView.addNetworkConnector or addConnector, limiting the ability to register arbitrary discovery transports.
Enforces access restrictions on runtime configuration changes to the broker, preventing unauthorized addition of network connectors that trigger the code-injection path.