CVE-2018-16492: Extend Prototype Pollution Vulnerability

MODERATE
Advisory Identifier: GHSA-qrmc-fj45-qfc2
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CWE-400
Published
Advisory Summary

CVE-2018-16492 is a MODERATE prototype pollution vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Extend libraries in the npm ecosystem. The issue involves prototype pollution in extend. Remediation is available by upgrading affected packages to version 3.0.2, 2.0.2.

CVE-2018-16492 at a Glance

CVE Identifier CVE-2018-16492
GHSA Identifier GHSA-qrmc-fj45-qfc2
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Extend
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2018-16492

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

extend fixed: 3.0.2 
npm install extend@3.0.2
extend fixed: 2.0.2 
npm install extend@2.0.2
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 extend

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2018-16492, inspect your project dependencies using npm:

npm ls extend

Analyze the terminal output to locate any version of Extend in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.0.2), your application is affected.

Note: The npm ls extend 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 CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Extend, 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

Versions of `extend` prior to 3.0.2 (for 3.x) and 2.0.2 (for 2.x) are vulnerable to Prototype Pollution. The `extend()` function allows attackers to modify the prototype of Object causing the addition or modification of an existing property that will exist on all objects. ## Recommendation If you're using `extend` 3.x upgrade to 3.0.2 or later. If you're using `extend` 2.x upgrade to 2.0.2 or later.

CVE-2018-16492 Affected Extend Versions

2 component(s)
Fixed Versions:
3.0.22.0.2
Product / Package Ecosystem Affected Versions Fixed Version
extend
npm/extend
npm
≥ 3.0.0
< 3.0.2
3.0.2
extend
npm/extend
npm
≥ 1.1.3
< 2.0.2
2.0.2

References

NVD — CVE-2018-16492 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-16492
Extend Source Repository REPOSITORY
https://github.com/github/advisory-database/pull/6695
Extend Source Repository REPOSITORY
https://github.com/justmoon/node-extend/pull/48
Security Fix Commit FIX COMMIT
https://github.com/justmoon/node-extend/commit/0e68e71d93507fcc391e398bc84abd0666b28190
hackerone.com/reports/381185 WEB
https://hackerone.com/reports/381185
Extend Source Repository REPOSITORY
https://github.com/justmoon/node-extend

Frequently Asked Questions

What is CVE-2018-16492?
CVE-2018-16492 is a security vulnerability in Extend involving Prototype Pollution in extend under CWE-400: Uncontrolled Resource Consumption.
Which Extend versions are affected?
Affected versions include releases prior to 3.0.2, 2.0.2 across affected packages: extend.
What version fixes CVE-2018-16492?
Upgrading to 3.0.2, 2.0.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is extend affected?
Yes, extend is affected in releases prior to 3.0.2, 2.0.2. Upgrade your dependency to 3.0.2, 2.0.2 or later.
What CWE is associated with CVE-2018-16492?
CVE-2018-16492 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check npm dependencies for CVE-2018-16492?
Run the dependency tree command: 'npm ls extend'. 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-qrmc-fj45-qfc2",
  "modified" : "2026-01-22T21:48:14Z",
  "published" : "2019-02-07T18:03:28Z",
  "aliases" : [ "CVE-2018-16492" ],
  "summary" : "Prototype Pollution in extend",
  "details" : "Versions of `extend` prior to 3.0.2 (for 3.x) and 2.0.2 (for 2.x) are vulnerable to Prototype Pollution. The `extend()` function allows attackers to modify the prototype of Object causing the addition or modification of an existing property that will exist on all objects.\n\n\n\n\n## Recommendation\n\nIf you're using `extend` 3.x upgrade to 3.0.2 or later.\nIf you're using `extend` 2.x upgrade to 2.0.2 or later.",
  "severity" : [ ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "extend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "extend"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.1.3"
      }, {
        "fixed" : "2.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-16492"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/github/advisory-database/pull/6695"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/justmoon/node-extend/pull/48"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/justmoon/node-extend/commit/0e68e71d93507fcc391e398bc84abd0666b28190"
  }, {
    "type" : "WEB",
    "url" : "https://hackerone.com/reports/381185"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/justmoon/node-extend"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:52:44Z",
    "nvd_published_at" : null
  }
}