OpenNMS JEXL sandbox bypass in Measurements REST API allows ROLE_USER to load arbitrary classes

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-19135
StatePUBLISHED
AssignerOpenNMS
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-13 05:17:22 UTC
Updated2026-08-13 13:17:48 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 5.4 MEDIUM from [email protected]

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

EPSS: 0.001730000 probability, percentile 0.069070000 (date 2026-08-13)

Problem Types: CWE-470 | CWE-470 CWE-470 Use of Externally-Controlled input to select classes or code ('unsafe reflection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
3.1CNACVSS5.4MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1 Breakdown

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

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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/8754 [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: tinyb0y (en)

CNA: Xanlar Agamalizade (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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