CVE-2021-3396

OpenNMS Horizon RCE via JEXL2 expression

OpenNMS Meridian 2016, 2017, 2018 before 2018.1.25, 2019 before 2019.1.16, and 2020 before 2020.1.5, Horizon 1.2 through 27.0.4, and Newts <1.5.3 has Incorrect Access Control, which allows local and remote code execution using JEXL expressions.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2021-3396 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (27.0.4); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

1. What is CVE-2021-3396? CVE-2021-3396 is a high-severity incorrect authorization vulnerability in org.opennms:opennms (maven), affecting versions >= 16.0.0, <= 27.0.3. It is fixed in 27.0.4. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2021-3396? CVE-2021-3396 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2021-3396?
   • org.opennms:opennms (maven) (versions >= 16.0.0, <= 27.0.3)
   • org.opennms.features:org.opennms.features.measurements (maven) (versions >= 16.0.0, <= 27.0.3)
   • org.opennms:opennms-provision (maven) (versions >= 16.0.0, <= 27.0.3)
   • org.opennms:opennms-util (maven) (versions >= 16.0.0, <= 27.0.3)
4. Is there a fix for CVE-2021-3396? Yes. CVE-2021-3396 is fixed in 27.0.4. Upgrade to this version or later.
5. Is CVE-2021-3396 exploitable, and should I be worried? Whether CVE-2021-3396 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-3396 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-3396?
   • Upgrade org.opennms:opennms to 27.0.4 or later
   • Upgrade org.opennms.features:org.opennms.features.measurements to 27.0.4 or later
   • Upgrade org.opennms:opennms-provision to 27.0.4 or later
   • Upgrade org.opennms:opennms-util to 27.0.4 or later

Other vulnerabilities in org.opennms:opennms