{"id":"CVE-2026-19596","state":"PUBLISHED","title":"OpenNMS XML collector XXE allows arbitrary file read from the OpenNMS host","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.\n\n\n\nThe 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.","publishedAt":"2026-09-10T20:08:50.816Z","updatedAt":"2026-09-10T20:27:45.533Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","source":"OpenNMS"},"assigner":"OpenNMS","products":["The OpenNMS Group Meridian","The OpenNMS Group Horizon"],"affected":[{"vendor":"The OpenNMS Group","product":"Meridian","defaultStatus":"unaffected","versions":[{"version":"2024.1.0","status":"affected","lessThan":"2024.3.13","versionType":"maven"},{"version":"2025.0.0","status":"affected","lessThan":"2025.0.10","versionType":"maven"}],"repo":"https://github.com/OpenNMS"},{"vendor":"The OpenNMS Group","product":"Horizon","defaultStatus":"unaffected","versions":[{"version":"36.0.0","status":"affected","lessThan":"36.0.4","versionType":"maven"}],"repo":"https://github.com/OpenNMS"}],"references":["https://github.com/OpenNMS/opennms/pull/8782"],"weaknesses":["CWE-611"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/19xxx/CVE-2026-19596.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-19596","state":"PUBLISHED","datePublished":"2026-09-10T20:08:50.816Z","dateUpdated":"2026-09-10T20:27:45.533Z","assignerShortName":"OpenNMS","assignerOrgId":"70b007e9-5235-4ee5-90b5-a71a81beeda0","dateReserved":"2026-08-12T06:24:26.987Z"},"containers":{"cna":{"title":"OpenNMS XML collector XXE allows arbitrary file read from the OpenNMS host","descriptions":[{"lang":"en","value":"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.\n\n\n\nThe 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."}],"affected":[{"vendor":"The OpenNMS Group","product":"Meridian","defaultStatus":"unaffected","versions":[{"version":"2024.1.0","status":"affected","lessThan":"2024.3.13","versionType":"maven"},{"version":"2025.0.0","status":"affected","lessThan":"2025.0.10","versionType":"maven"}],"repo":"https://github.com/OpenNMS"},{"vendor":"The OpenNMS Group","product":"Horizon","defaultStatus":"unaffected","versions":[{"version":"36.0.0","status":"affected","lessThan":"36.0.4","versionType":"maven"}],"repo":"https://github.com/OpenNMS"}],"references":[{"url":"https://github.com/OpenNMS/opennms/pull/8782","tags":["patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","baseSeverity":"MEDIUM","baseScore":5.9,"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-611","lang":"en","description":"CWE-611 Improper Restriction of XML External Entity Reference","type":"CWE"}]}],"providerMetadata":{"shortName":"OpenNMS","orgId":"70b007e9-5235-4ee5-90b5-a71a81beeda0","dateUpdated":"2026-09-10T20:08:50.816Z"},"solutions":[{"lang":"en","value":"Upgrade to Meridian 2024.3.13, 2025.0.10 and Horizon 36.0.4 or newer.","supportingMedia":[{"type":"text/html","base64":false,"value":"<p>Upgrade to Meridian 2024.3.13, 2025.0.10 and Horizon 36.0.4 or newer.</p>"}]}],"credits":[{"lang":"en","value":"Keith Lee, Foregenix","type":"finder"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.4"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-10T20:27:39.274555Z","id":"CVE-2026-19596","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-10T20:27:45.533Z"}}]}}}