CVE-2026-111235

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/OpenNMS/opennms/pull/8934

Configurations

No configuration.

History

15 Oct 2026, 19:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-15 19:17

Updated : 2026-10-16 20:17

NVD link : CVE-2026-111235

Mitre link : CVE-2026-111235

CVE.ORG link : CVE-2026-111235

JSON object : View

Products Affected

No product.

CWE

CWE-204

Observable Response Discrepancy

CWE-862

Missing Authorization

CWE-863

Incorrect Authorization

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