GHSA-mmqv-m45h-q2hp: Localeval Sandbox Breakout / Arbitrary Code Vulnerability

CRITICAL
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Advisory Summary

GHSA-mmqv-m45h-q2hp is a CRITICAL sandbox breakout / arbitrary code vulnerability (General Security Weakness) affecting Localeval libraries in the npm ecosystem. The issue involves sandbox breakout / arbitrary code execution in localeval. Remediation is available by upgrading affected packages to version 15.3.0.

GHSA-mmqv-m45h-q2hp at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-mmqv-m45h-q2hp
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification General Security Weakness
Affected Product Localeval
Package Ecosystem npm
Published Date
Last Updated

How to Fix GHSA-mmqv-m45h-q2hp

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

localeval fixed: 15.3.0 
npm install localeval@15.3.0
Verify Direct and Transitive Dependencies

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

npm ls localeval

How to Check if You Are Affected

To determine whether your Node.js application is affected by GHSA-mmqv-m45h-q2hp, inspect your project dependencies using npm:

npm ls localeval

Analyze the terminal output to locate any version of Localeval in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 15.3.0), your application is affected.

Note: The npm ls localeval command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Localeval, 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

All versions of `localeval` are vulnerable to Sandbox Escape leading to Remote Code Execution. The package fails to restrict access to the main context through `constructor.constructor`. This may allow attackers to execute arbitrary code in the system. Evaluating the payload ``` constructor.constructor("return process.env")() ``` returns the contents of `process.env`. ## Recommendation No fix is currently available. Consider using an alternative package until a fix is made available.

GHSA-mmqv-m45h-q2hp Affected Localeval Versions

1 component(s)
Fixed Versions:
15.3.0
Product / Package Ecosystem Affected Versions Fixed Version
localeval
npm/localeval
npm
< 15.3.0
15.3.0

References

Localeval Source Repository REPOSITORY
https://github.com/espadrine/localeval/issues/9
Security Fix Commit FIX COMMIT
https://github.com/espadrine/localeval/commit/823f112c793b8fae051eeddad61d4ed29804a56c
Security Fix Commit FIX COMMIT
https://github.com/espadrine/localeval/commit/ce985eba77a5f89a7f718727cbaa7fb14da40335
Localeval Source Repository REPOSITORY
https://github.com/espadrine/localeval

Frequently Asked Questions

What is GHSA-mmqv-m45h-q2hp?
GHSA-mmqv-m45h-q2hp is a security vulnerability in Localeval involving Sandbox Breakout / Arbitrary Code Execution in localeval under General Security Weakness.
Which Localeval versions are affected?
Affected versions include releases prior to 15.3.0 across affected packages: localeval.
What version fixes GHSA-mmqv-m45h-q2hp?
Upgrading to 15.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is localeval affected?
Yes, localeval is affected in releases prior to 15.3.0. Upgrade your dependency to 15.3.0 or later.
What CWE is associated with GHSA-mmqv-m45h-q2hp?
GHSA-mmqv-m45h-q2hp is classified under General Security Weakness.
How can I check npm dependencies for GHSA-mmqv-m45h-q2hp?
Run the dependency tree command: 'npm ls localeval'. 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-mmqv-m45h-q2hp",
  "modified" : "2026-01-16T14:47:29Z",
  "published" : "2020-09-04T15:22:40Z",
  "aliases" : [ ],
  "summary" : "Sandbox Breakout / Arbitrary Code Execution in localeval",
  "details" : "All versions of `localeval` are vulnerable to Sandbox Escape leading to Remote Code Execution. The package fails to restrict access to the main context through `constructor.constructor`. This may allow attackers to execute arbitrary code in the system.  Evaluating the payload \n```\nconstructor.constructor(\"return process.env\")()\n``` \n\nreturns the contents of `process.env`.\n\n\n## Recommendation\n\nNo fix is currently available. Consider using an alternative package until a fix is made available.",
  "severity" : [ ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "localeval"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "15.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/espadrine/localeval/issues/9"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/espadrine/localeval/commit/823f112c793b8fae051eeddad61d4ed29804a56c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/espadrine/localeval/commit/ce985eba77a5f89a7f718727cbaa7fb14da40335"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/espadrine/localeval"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-08-31T18:55:41Z",
    "nvd_published_at" : null
  }
}