CVE-2021-23700: Merge deep2 Prototype Pollution Vulnerability

MODERATE
Advisory Identifier: GHSA-j28q-p8ww-cp87
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CVSS 6.5
CWE-1321
Published
Advisory Summary

CVE-2021-23700 is a MODERATE (CVSS 6.5) prototype pollution vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Merge deep2 libraries in the npm ecosystem. The issue involves prototype pollution in merge-deep2.. Remediation is available in the latest vendor maintenance releases.

CVE-2021-23700 at a Glance

CVE Identifier CVE-2021-23700
GHSA Identifier GHSA-j28q-p8ww-cp87
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Merge deep2
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 6.5

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

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

How to Fix CVE-2021-23700

To remediate this vulnerability, upgrade all affected Merge deep2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

merge-deep2 fixed: Latest secure release 
npm install merge-deep2@Latest secure release
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 merge-deep2

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-23700, inspect your project dependencies using npm:

npm ls merge-deep2

Analyze the terminal output to locate any version of Merge deep2 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 npm ls merge-deep2 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-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Merge deep2, 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 package merge-deep2 are vulnerable to Prototype Pollution via the mergeDeep() function.

CVE-2021-23700 Affected Merge deep2 Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
merge-deep2
npm/merge-deep2
npm
≤ 3.0.6

References

NVD — CVE-2021-23700 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-23700
Merge deep2 Source Repository REPOSITORY
https://github.com/luyuan/merge-deep
snyk.io/vuln/snyk-js-merged... WEB
https://snyk.io/vuln/SNYK-JS-MERGEDEEP2-1727593

Frequently Asked Questions

What is CVE-2021-23700?
CVE-2021-23700 is a security vulnerability in Merge deep2 involving Prototype Pollution in merge-deep2. under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Merge deep2 versions are affected?
Affected versions include releases prior to current release patches across affected packages: merge-deep2.
What version fixes CVE-2021-23700?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is merge-deep2 affected?
Yes, merge-deep2 is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2021-23700?
CVE-2021-23700 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.
What CWE is associated with CVE-2021-23700?
CVE-2021-23700 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2021-23700?
Run the dependency tree command: 'npm ls merge-deep2'. 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-j28q-p8ww-cp87",
  "modified" : "2021-12-15T15:23:03Z",
  "published" : "2021-12-16T14:33:09Z",
  "aliases" : [ "CVE-2021-23700" ],
  "summary" : "Prototype Pollution in merge-deep2.",
  "details" : "All versions of package merge-deep2 are vulnerable to Prototype Pollution via the mergeDeep() function.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "merge-deep2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "3.0.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23700"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/luyuan/merge-deep"
  }, {
    "type" : "WEB",
    "url" : "https://snyk.io/vuln/SNYK-JS-MERGEDEEP2-1727593"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-12-14T14:33:34Z",
    "nvd_published_at" : "2021-12-10T20:15:00Z"
  }
}