CVE-2026-89054 OpenNMS Horizon - Broken Access Control

OpenNMS Horizon contains a missing authorization vulnerability caused by lack of authorization enforcement on PATCH endpoints in /api/v2 REST API, letting unauthenticated attackers disable event and SNMP data collection, exploit requires attacker to access the web UI.

CVSS base score 8.2 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.51% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Published
10 September 2026
Updated
15 October 2026
Weakness
CWE-862

Vendor fix

Upgrade to Horizon 36.0.4 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

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