CVE-2026-19596
OpenNMS XML collector XXE allows arbitrary file read from the OpenNMS host
- State
- Published
- Severity
- 5.9 Medium
- Published
- Sep 10, 2026
- Updated
- Sep 10, 2026
- Reserved
- Aug 12, 2026
Description
An XML External Entity (XXE) vulnerability exists in the XML collector of multiple versions of OpenNMS Meridian and Horizon. When OpenNMS collects XML from a source whose response is attacker-controlled (for example a compromised monitored host or an HTTP man-in-the-middle position), the collector's XML parser resolves external entities and external DTDs. This allows an attacker to read files accessible to the OpenNMS service account, including database credentials, and to induce out-of-band requests.
The solution is to upgrade to Meridian 2024.3.13, 2025.0.10 and Horizon 36.0.4 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 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | OpenNMS |
Weaknesses
- CWE-611 Improper Restriction of XML External Entity Reference
Affected Products
| Product | Versions |
|---|---|
MeridianThe OpenNMS Group |
|
HorizonThe OpenNMS Group |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.