A missing authorization vulnerability in OpenNMS Horizon allows configuration changes without authentication. The Spring Security policy for the /api/v2 REST API defines authorization rules for every HTTP method except PATCH, so the shipped @PATCH configuration endpoints for event configuration and SNMP data collection (which enable and disable event definitions and data-collection sources) are reachable with no authorization enforced. An unauthenticated attacker able to reach the web UI can disable event definitions and SNMP data collection, suppressing event and alarm generation and stopping metric collection - silently degrading monitoring and detection - with the change persisted and reloaded into the running system.



The solution is to upgrade to 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.

Project Subscriptions

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Advisories

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Fixes

Solution

Upgrade to Horizon 36.0.4 or newer.


Workaround

No workaround given by the vendor.

History

Thu, 10 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 10 Sep 2026 19:45:00 +0000

Type Values Removed Values Added
Description A missing authorization vulnerability in OpenNMS Horizon allows configuration changes without authentication. The Spring Security policy for the /api/v2 REST API defines authorization rules for every HTTP method except PATCH, so the shipped @PATCH configuration endpoints for event configuration and SNMP data collection (which enable and disable event definitions and data-collection sources) are reachable with no authorization enforced. An unauthenticated attacker able to reach the web UI can disable event definitions and SNMP data collection, suppressing event and alarm generation and stopping metric collection - silently degrading monitoring and detection - with the change persisted and reloaded into the running system. The solution is to upgrade to 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.
Title OpenNMS missing authorization on /api/v2 PATCH endpoints allows unauthenticated configuration changes
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: OpenNMS

Published:

Updated: 2026-09-10T20:03:12.742Z

Reserved: 2026-09-10T17:29:48.545Z

Link: CVE-2026-89054

cve-icon Vulnrichment

Updated: 2026-09-10T20:03:10.007Z

cve-icon NVD

Status : Received

Published: 2026-09-10T20:17:31.973

Modified: 2026-09-10T20:17:31.973

Link: CVE-2026-89054

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses