github.com
https://github.com/OpenNMS/opennms/pull/8754 CVE-2026-19135
MEDIUM
OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classes
Record summary
CVE-2026-19135 has a selected CVSS score of 5.4 (medium).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableNo
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Aug 13, 2026 · Source: CVE List
Affected products and versions
2| Product | Source | Version range | Status |
|---|---|---|---|
Default status: unaffected | CVE List | 36.0.0 to < 36.0.3 | affected |
Default status: unaffected | CVE List | 2024.1.0 to < 2024.3.12 | affected |
| 2025.0.0 to < 2025.0.9 | affected |
References
2nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-19135