SEPTEMBER 14, 2026
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Case File

CVE-2026-19596

MEDIUM · CVSS 5.9 EPSS 0.21% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-10 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

An XML External Entity (XXE) vulnerability in the XML collector of multiple versions of OpenNMS Meridian and Horizon allows attackers to exploit XML parsing to access sensitive files, such as database credentials, from the OpenNMS service account. This vulnerability is particularly concerning for organizations using these versions, as it can lead to unauthorized data exposure and out-of-band requests. Users of OpenNMS should prioritize upgrading to the specified secure versions to mitigate this risk.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-19596
Severity
MEDIUM
CVSS
5.9
EPSS
0.21%

Original NVD 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.