OpenNMS v2 Alarm REST API inverted authorization check lets ROLE_REST users acknowledge alarms as any user and bypass read-only

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-19182
StatePUBLISHED
AssignerOpenNMS
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-13 05:17:22 UTC
Updated2026-08-13 13:17:48 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v3.1 4.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS: 0.001520000 probability, percentile 0.048960000 (date 2026-08-13)

Problem Types: CWE-863 | CWE-863 CWE-863 Incorrect Authorization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
3.1CNACVSS4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA The OpenNMS Group Meridian affected 2024.1.0 2024.3.12 maven Not specified
CNA The OpenNMS Group Meridian affected 2025.0.0 2025.0.9 maven Not specified
CNA The OpenNMS Group Horizon affected 36.0.0 36.0.3 maven Not specified

References

ReferenceSourceLinkTags
github.com/OpenNMS/opennms/pull/8755 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Santosh Kumar Puppala (en)

Additional Advisory Data

Solutions

CNA: Upgrade to Meridian 2024.3.12, 2025.0.9 and Horizon 36.0.3 or newer.

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