--- title: "OpenNMS Meridian & Horizon - Authorization Bypass" description: "OpenNMS Meridian and Horizon contain an authorization bypass caused by case-sensitive HTTP method checks missing terminal deny rules in REST API Spring Security filter chains, letting remote unauthenticated attackers read and modify resources, exploit requires sending requests with non-canonical HTTP methods." url: https://panop.io/threat-heartbeat/CVE-2026-111235/ --- # CVE-2026-111235 OpenNMS Meridian & Horizon - Authorization Bypass OpenNMS Meridian and Horizon contain an authorization bypass caused by case-sensitive HTTP method checks missing terminal deny rules in REST API Spring Security filter chains, letting remote unauthenticated attackers read and modify resources, exploit requires sending requests with non-canonical HTTP methods. CVSS base score 9.1 /10 Critical CISA KEV Not listed Public exploit None known Authentication Not required [View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-111235) ## Details Type Broken Access Control Impact Broken Access Control, Data Tampering, Information Disclosure CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Published 15 October 2026 Updated 16 October 2026 Weakness [CWE-204](https://cwe.mitre.org/data/definitions/204.html) ## Vendor fix Upgrade to Meridian 2024.3.14, 2025.0.11, 2026.0.1 and Horizon 36.0.5 or newer. Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them. ## References - [https://nvd.nist.gov/vuln/detail/CVE-2026-111235](https://nvd.nist.gov/vuln/detail/CVE-2026-111235) - [https://github.com/OpenNMS/opennms/pull/8934](https://github.com/OpenNMS/opennms/pull/8934) [← All CVEs](https://panop.io/threat-heartbeat/) ## What this record can't tell you - Whether you run the affected software, and where - Whether an attacker can actually reach and exploit it - The misconfigurations that never get a CVE number - What it would cost the business, ranked into what to fix first Panop answers these inside your environment, for this CVE and every other finding. [Book a demo](https://panop.io/demo)