CVE-2026-19182
OpenNMS v2 Alarm REST API inverted authorization check lets ROLE_REST users acknowledge alarms as any user and bypass read-only
Description
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.
INFO
Published Date :
Aug. 13, 2026, 5:17 a.m.
Last Modified :
Aug. 13, 2026, 5:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 70b007e9-5235-4ee5-90b5-a71a81beeda0 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Upgrade to Meridian 2024.3.12 or newer.
- Upgrade to Horizon 36.0.3 or newer.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-19182.
| URL | Resource |
|---|---|
| https://github.com/OpenNMS/opennms/pull/8755 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-19182 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-19182
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-19182 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-19182 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 13, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/OpenNMS', 'vendor': 'The OpenNMS Group', 'product': 'Meridian', 'versions': [{'status': 'affected', 'version': '2024.1.0', 'lessThan': '2024.3.12', 'versionType': 'maven'}, {'status': 'affected', 'version': '2025.0.0', 'lessThan': '2025.0.9', 'versionType': 'maven'}], 'defaultStatus': 'unaffected'}, {'repo': 'https://github.com/OpenNMS', 'vendor': 'The OpenNMS Group', 'product': 'Horizon', 'versions': [{'status': 'affected', 'version': '36.0.0', 'lessThan': '36.0.3', 'versionType': 'maven'}], 'defaultStatus': 'unaffected'}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-863 Added Reference https://github.com/OpenNMS/opennms/pull/8755