CVE-2026-19135

Summary

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 Java classes on the server. This can potentially allow an attacker to gain access to confidential information and compromise integrity.

The solution is to upgrade to Meridian 2024.3.12, 2025.0.9 and Horizon 36.0.3 or newer. Meridian and Horizon installation instructions state that they are intended for installation within an organization's private networks and should not be directly accessible from the Internet.

Affected Software

VendorProductVersion RangeStatus
The OpenNMS GroupMeridian2024.1.0 < 2024.3.12affected
The OpenNMS GroupMeridian2025.0.0 < 2025.0.9affected
The OpenNMS GroupHorizon36.0.0 < 36.0.3affected

Weaknesses

  • CWE-470: CWE-470 Use of Externally-Controlled input to select classes or code ('unsafe reflection')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References