CVSS 3.1
5.4 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:NCVE-2026-127236 OpenNMS argument injection in ad-hoc RRD graphs
Medium (5.4) in the opennms group. EPSS 0.4% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.4% estimated probability of exploitation activity in the next 30 days; 32nd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-88 Improper Neutralization of Argument Delimiters in a Command (Argument Injection)
- OWASP Top 10
- A05:2025 Injection
- Published
- Modified
- Assigned by
- OpenNMS (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- the opennms group:horizon
- the opennms group:meridian
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| The OpenNMS Group Meridian | from 2024.1.0 before 2024.3.15 |
| The OpenNMS Group Meridian | from 2025.0.0 before 2025.0.12 |
| The OpenNMS Group Meridian | from 2026.0.0 before 2026.0.2 |
| The OpenNMS Group Horizon | from 36.0.0 before 36.0.6 |
Attack patterns (CAPEC)
- CAPEC-41 Using Meta-characters in E-mail Headers to Inject Malicious Payloads Likelihood: High · Severity: High
- CAPEC-88 OS Command Injection Likelihood: High · Severity: High
- CAPEC-137 Parameter Injection Likelihood: Medium · Severity: Medium
- CAPEC-174 Flash Parameter Injection Likelihood: High · Severity: Medium
- CAPEC-460 HTTP Parameter Pollution (HPP) Severity: Medium
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.