CVE-2026-19135: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-q2r2-4mh9-4268
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CVSS 5.4
CWE-470
Published
Advisory Summary

CVE-2026-19135 is a MODERATE (CVSS 5.4) security vulnerability vulnerability (CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-19135 at a Glance

CVE Identifier CVE-2026-19135
GHSA Identifier GHSA-q2r2-4mh9-4268
Severity MODERATE
CVSS v3.1 Base Score 5.4
CWE Classification CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 5.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-19135

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-19135, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection'), where the product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

References

NVD — CVE-2026-19135 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19135
Software Source Repository REPOSITORY
https://github.com/OpenNMS/opennms/pull/8754

Frequently Asked Questions

What is CVE-2026-19135?
CVE-2026-19135 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-19135?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-19135?
CVE-2026-19135 has a CVSS v3.1 base score of 5.4 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N.
What CWE is associated with CVE-2026-19135?
CVE-2026-19135 is classified under CWE-470: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') (The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.).
How can I check Maven dependencies for CVE-2026-19135?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q2r2-4mh9-4268",
  "modified" : "2026-08-13T06:33:50Z",
  "published" : "2026-08-13T06:33:50Z",
  "aliases" : [ "CVE-2026-19135" ],
  "details" : "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.\n\nThe 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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-19135"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OpenNMS/opennms/pull/8754"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-470" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-13T05:17:22Z"
  }
}