Answer in brief
CVE-2026-19135 records a Unknown severity vulnerability in OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classes. The current sources do not mark it as known exploited. The current feed maps The OpenNMS Group/Horizon (generic), The OpenNMS Group/Meridian (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps The OpenNMS Group/Horizon (generic), The OpenNMS Group/Meridian (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| The OpenNMS Group/Horizongeneric | >=36.0.0 <36.0.3 | 36.0.3 |
| The OpenNMS Group/Meridiangeneric | >=2024.1.0 <2024.3.12 || >=2025.0.0 <2025.0.9 | 2024.3.12, 2025.0.9 |
Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 13, 2026
A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to the Measurements REST API that escapes the sandbox and loads arbitrary Java classes on the server. This can potentially allow an attacker to gain access to confidential information and compromise integrity. 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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-19135 records a Unknown severity vulnerability in OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classes. The current sources do not mark it as known exploited. The current feed maps The OpenNMS Group/Horizon (generic), The OpenNMS Group/Meridian (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps The OpenNMS Group/Horizon (generic), The OpenNMS Group/Meridian (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| The OpenNMS Group/Horizongeneric | >=36.0.0 <36.0.3 | 36.0.3 |
| The OpenNMS Group/Meridiangeneric | >=2024.1.0 <2024.3.12 || >=2025.0.0 <2025.0.9 | 2024.3.12, 2025.0.9 |
Published upstream
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 13, 2026
A JEXL expression sandbox bypass exists in multiple versions of OpenNMS Meridian and Horizon. A low-privileged authenticated user can submit a crafted expression to the Measurements REST API that escapes the sandbox and loads arbitrary Java classes on the server. This can potentially allow an attacker to gain access to confidential information and compromise integrity. 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.
Quoted source text, attributed separately from HOL analysis.