CVE-2026-19135
OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classes
- State
- Published
- Severity
- 5.4 Medium
- Published
- Aug 13, 2026
- Updated
- Aug 13, 2026
- Reserved
- Aug 6, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N | OpenNMS |
Weaknesses
- CWE-470 Use of Externally-Controlled input to select classes or code ('unsafe reflection')
Affected Products
| Product | Versions |
|---|---|
MeridianThe OpenNMS Group |
|
HorizonThe OpenNMS Group |
|
References
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