CVE-2026-127236

OpenNMS argument injection in ad-hoc RRD graphs

Published Nov 12, 2026 CVSS 3.1 · 5.4 Medium EPSS n/a KEV · Not listed
Description
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.

Remediation

Vendor Solution

Upgrade to Meridian 2024.3.15, 2025.0.12, 2026.0.2 and Horizon 36.0.6 or newer.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Opennms
Opennms horizon
Opennms meridian
The Opennms Group
The Opennms Group horizon
The Opennms Group meridian
Vendors & Products Opennms
Opennms horizon
Opennms meridian
The Opennms Group
The Opennms Group horizon
The Opennms Group meridian
Type Values Removed Values Added
Description 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.
Title OpenNMS argument injection in ad-hoc RRD graphs
Weaknesses CWE-88
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
OpenNMS
Published
Updated
Nov 12, 2026, 6:04 PM
Reserved
Nov 12, 2026, 5:14 PM
Status
Awaiting Analysis
Published
Nov 12, 2026, 7:17 PM
Modified
Nov 12, 2026, 9:35 PM