Vulnerability in The Opennms Group Horizon

CVE-2026-19135

A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to the Measurements REST API that escapes the sandbox and loads arbitrary Jav…

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-19135?
CVE-2026-19135 is a medium-severity vulnerability in The Opennms Group Horizon, classified under Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection). CVSS score: 5.4/10. Published 2026-08-13.
How severe is CVE-2026-19135?
Medium severity. CVSS v3 base score is 5.4 out of 10.