CVE-2026-127236
OpenNMS argument injection in ad-hoc RRD graphs
An argument injection vulnerability exists in the ad-hoc RRD graph feature of multiple versions of OpenNMS Meridian and Horizon. The ad-hoc graph endpoint (GET /graph/graph.png?adhoc=true) copies request parameters into the rrdtool command line without validation. A low-privileged authenticated user (ROLE_USER or ROLE_DASHBOARD) can insert extra rrdtool arguments. An injected --daemon argument makes the server connect to an attacker-chosen address, which is a server-side request forgery. An injected DEF statement reads a local RRD file by absolute path. The command runs through exec with an argument array and no shell, so arbitrary operating system command execution is not possible. The fix validates the ad-hoc graph parameters against allowlists. The solution is to upgrade to Meridian 2024.3.15, 2025.0.12, 2026.0.2 and Horizon 36.0.6 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.
Fixes and workarounds
Fix
Upgrade to Meridian 2024.3.15, 2025.0.12, 2026.0.2 and Horizon 36.0.6 or newer.
Source: CNA: OpenNMSFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: OpenNMSAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Meridian The OpenNMS Group |
≥ 2024.1.0; < 2024.3.15 (affected, maven) ≥ 2025.0.0; < 2025.0.12 (affected, maven) ≥ 2026.0.0; < 2026.0.2 (affected, maven) Other versions: unaffected |
CNA: OpenNMS |
| Horizon The OpenNMS Group |
≥ 36.0.0; < 36.0.6 (affected, maven)
Other versions: unaffected |
CNA: OpenNMS |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 5.4 medium |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N | CNA: OpenNMS |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/OpenNMS/opennms/pull/9065CNA: OpenNMS · patch
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