Read the docs
TI-2026-15665 Aliases CVE-2026-19182GHSA-r53w-fffc-9ppv

Incorrect authorization in OpenNMS Group Meridian

Priority LOW 20CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

An incorrect authorization check in the v2 Alarm REST API in OpenNMS Meridian and Horizon allows a low-privileged authenticated user (ROLE_REST) to acknowledge, escalate, or clear alarms recorded as an arbitrary username, and, when also assigned ROLE_READONLY, to modify alarm state despite the read-only restriction. A credential check that should restrict these operations is guarded by an inverted condition, so it never executes for a real (non-blank) username. This can potentially allow an attacker to compromise the integrity of alarm state and audit records. The solution is to upgrade to Meridian 2024.3.12, 2025.0.9 and Horizon 36.0.3 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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00254 17th percentileScored 2026-11-07
Fix Fixed Meridian (The OpenNMS Group): 2024.3.12, 2025.0.9Horizon (The OpenNMS Group): 36.0.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
The OpenNMS GroupMeridian2024.1.0 to before 2024.3.12; 2025.0.0 to before 2025.0.92024.3.12, 2025.0.9Patch availableCNA
The OpenNMS GroupHorizon36.0.0 to before 36.0.336.0.3Patch availableCNA
  • Meridian VendorThe OpenNMS Group Affected 2024.1.0 to before 2024.3.12; 2025.0.0 to before 2025.0.9 Fixed in 2024.3.12, 2025.0.9 Patch available CNA
  • Horizon VendorThe OpenNMS Group Affected 36.0.0 to before 36.0.3 Fixed in 36.0.3 Patch available CNA

Remediation

  • Fix · CNA Meridian (The OpenNMS Group) Fixed in 2024.3.12, 2025.0.9
  • Fix · CNA Horizon (The OpenNMS Group) Fixed in 36.0.3

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    The OpenNMS Group Horizon, Meridian 2024.3.12, 2025.0.9, 36.0.3

    2 records Highest priority Priority LOW 2 LOW

    Other records, highest priority first

    • TI-2026-15621 OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classesPriority LOW 24
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-19182
  2. 2026-10-03 Alias added: GHSA-r53w-fffc-9ppv

References

Patch 1

  • TI-2021-07941 Cross-site request forgery in OpenNMS CVSS 3.1HIGH 8.8
  • TI-2021-07943 Cross-site scripting in OpenNMS CVSS 3.1MEDIUM 4.8
  • TI-2021-07939 Cross-site scripting in OpenNMS CVSS 3.1MEDIUM 4.8
  • TI-2021-07940 Cross-site request forgery in OpenNMS CVSS 3.1MEDIUM 4.3
  • TI-2015-06530 OpenNMS has a default password of rtc for the rtc account, which makes it easier for… CVSS 2.0HIGH 10.0
  • TI-2026-74978 OpenNMS REST authorization bypass via non-canonical HTTP method CVSS 3.1CRITICAL 9.1
See all 38 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences