CVE-2026-40466 — apache-activemq
HIGHCVE-2026-40466 is a high-severity (CVSS 8.8) Improper Input Validation vulnerability in org.apache.activemq:apache-activemq. A fix is available for org.apache.activemq:apache-activemq — see the affected versions and patch details below.
Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Possible bypass of CVE-2026-34197 via HTTP discovery second-stage URI
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40466.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-40466 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.apache.activemq:apache-activemq☕org.apache.activemq:activemq-all☕org.apache.activemq:activemq-broker☕org.apache.activemq:apache-activemq☕org.apache.activemq:activemq-all☕org.apache.activemq:activemq-brokerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.activemq:apache-activemq | all versions | 5.19.6org.apache.activemq:apache-activemq:5.19.6 |
| ☕Maven | org.apache.activemq:activemq-all | all versions | 5.19.6org.apache.activemq:activemq-all:5.19.6 |
| ☕Maven | org.apache.activemq:activemq-broker | all versions | 5.19.6org.apache.activemq:activemq-broker:5.19.6 |
| ☕Maven | org.apache.activemq:apache-activemq | ≥ 6.0.0&&< 6.2.5 | 6.2.5org.apache.activemq:apache-activemq:6.2.5 |
| ☕Maven | org.apache.activemq:activemq-all | ≥ 6.0.0&&< 6.2.5 | 6.2.5org.apache.activemq:activemq-all:6.2.5 |
| ☕Maven | org.apache.activemq:activemq-broker | ≥ 6.0.0&&< 6.2.5 | 6.2.5org.apache.activemq:activemq-broker:6.2.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.activemq:apache-activemq, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.activemq:apache-activemq to 5.19.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40466 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-40466 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-40466. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
How to detect CVE-2026-40466
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2026-40466 -u https://target- Template
- Apache ActiveMQ - Remote Code Execution via HTTP Discovery Transport Bypass
- Severity
- high
- Impact
- Authenticated attackers can execute arbitrary code on the broker JVM, potentially leading to full system compromise.
- Remediation
- Attacker must be authenticated and activemq-http module must be on classpath.
Template by ProjectDiscovery nuclei-templates (DhiyaneshDk), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2026-40466 in your dependencies?
O3 Security finds CVE-2026-40466 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.