Vulnerabilities

Vulnerability · CVE-2026-111235

An authorization bypass vulnerability exists in the REST API of multiple versions of OpenNMS Meridian and Horizon.

Published Oct 15, 2026 · catalog updated Oct 15, 2026 · An authorization bypass vulnerability

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No confirmed exploitation is on record for CVE-2026-111235. EPSS is 0.38%. Act only if a listed version of An authorization bypass vulnerability is installed.

Severity

Critical9.1

Known exploitation

Not in CISA/VulnCheck KEV

EPSS

0.38%

Remediation

Not established

Affected products

See sources for product scope

An authorization bypass vulnerability exists in the REST API of multiple versions of OpenNMS Meridian and Horizon. The /rest/** Spring Security filter chains authorize requests with intercept-url rules that name the HTTP method as an uppercase token, compare the method case-sensitively, and have no terminal deny rule. A request that uses a non-canonical (for example lowercase) method token matches no rule and is processed without authentication. A remote, unauthenticated attacker can read the monitored inventory and can create, modify, or delete resources through the REST API, which includes injecting events to fabricate or suppress alarms. The /rest/alarms chain has the same missing deny rule and discloses whether an alarm exists through a difference in the response. The fix adds a terminal deny rule to each REST filter chain. The solution is to upgrade to Meridian 2024.3.14, 2025.0.11, 2026.0.1 and Horizon 36.0.5 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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.