CVE-2021-23358: Underscore Arbitrary Code Execution Vulnerability

Q: What is CVE-2021-23358?

CVE-2021-23358 is a security vulnerability in Underscore involving Arbitrary Code Execution in underscore under CWE-94: Improper Control of Generation of Code ('Code Injection').

Q: Which Underscore versions are affected?

Affected versions include releases prior to 1.12.1 across affected packages: underscore.

Q: What version fixes CVE-2021-23358?

Upgrading to 1.12.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is underscore affected?

Yes, underscore is affected in releases prior to 1.12.1. Upgrade your dependency to 1.12.1 or later.

Q: What is the CVSS score of CVE-2021-23358?

CVE-2021-23358 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Q: What CWE is associated with CVE-2021-23358?

CVE-2021-23358 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).

Q: How can I check npm dependencies for CVE-2021-23358?

Run the dependency tree command: 'npm ls underscore'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

CRITICAL

Advisory Identifier: GHSA-cf4h-3jhx-xvhq

CVSS 9.8

CWE-94

Published 2021-05-06

Advisory Summary

CVE-2021-23358 is a CRITICAL (CVSS 9.8) arbitrary code execution vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Underscore libraries in the npm ecosystem. The issue involves arbitrary code execution in underscore. Remediation is available by upgrading affected packages to version 1.12.1.

CVE-2021-23358 at a Glance

CVE Identifier CVE-2021-23358

GHSA Identifier GHSA-cf4h-3jhx-xvhq

Severity CRITICAL

CVSS v3.1 Base Score 9.8

CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')

Affected Product Underscore

Package Ecosystem npm

Published Date 2021-05-06

Last Updated 2025-11-04

Security Impact

CVSS: 9.8

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:H/I:H/A:H).

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 High (C:H)

Integrity High (I:H)

Availability High (A:H)

How to Fix CVE-2021-23358

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

underscore fixed: 1.12.1

npm install underscore@1.12.1

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 underscore

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-23358, inspect your project dependencies using npm:

npm ls underscore

Analyze the terminal output to locate any version of Underscore in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.12.1), your application is affected.

Note: The npm ls underscore 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Underscore, 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

The package `underscore` from 1.13.0-0 and before 1.13.0-2, from 1.3.2 and before 1.12.1 are vulnerable to Arbitrary Code Execution via the template function, particularly when a variable property is passed as an argument as it is not sanitized.

CVE-2021-23358 Affected Underscore Versions

1 component(s)

Fixed Versions:

1.12.1

Product / Package	Ecosystem	Affected Versions	Fixed Version
underscore npm/underscore	npm	≥ 1.3.2 < 1.12.1	1.12.1

References

NVD — CVE-2021-23358 NVD

https://nvd.nist.gov/vuln/detail/CVE-2021-23358

Underscore Source Repository REPOSITORY

https://github.com/jashkenas/underscore/pull/2917

Security Fix Commit FIX COMMIT

https://github.com/jashkenas/underscore/commit/4c73526d43838ad6ab43a6134728776632adeb66

Underscore Security Information SECURITY

https://www.tenable.com/security/tns-2021-14

www.npmjs.com/package/underscore WEB

https://www.npmjs.com/package/underscore

Underscore Security Information SECURITY

https://www.debian.org/security/2021/dsa-4883

snyk.io/vuln/snyk-js-unders... WEB

https://snyk.io/vuln/SNYK-JS-UNDERSCORE-1080984

snyk.io/vuln/snyk-java-orgw... WEB

https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1081503

snyk.io/vuln/snyk-java-orgw... WEB

https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBJASHKENAS-1081505

snyk.io/vuln/snyk-java-orgw... WEB

https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-1081504

Underscore Security Information SECURITY

https://security.netapp.com/advisory/ntap-20241108-0002

Underscore Security Information SECURITY

https://security.netapp.com/advisory/ntap-20240808-0003

lists.fedoraproject.org/archives/list/packa... WEB

https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FGEE7U4Z655A2MK5EW4UQQZ7B64XJWBV

lists.fedoraproject.org/archives/list/packa... WEB

https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EOKATXXETD2PF3OR36Q5PD2VSVAR6J5Z

lists.fedoraproject.org/archives/list/packa... WEB

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FGEE7U4Z655A2MK5EW4UQQZ7B64XJWBV

lists.fedoraproject.org/archives/list/packa... WEB

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKATXXETD2PF3OR36Q5PD2VSVAR6J5Z

lists.debian.org/debian-lts-announce... WEB

https://lists.debian.org/debian-lts-announce/2021/03/msg00038.html

lists.apache.org/thread.html/re69ee4... WEB

https://lists.apache.org/thread.html/re69ee408b3983b43e9c4a82a9a17cbbf8681bb91a4b61b46f365aeaf@%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/re69ee4... WEB

https://lists.apache.org/thread.html/re69ee408b3983b43e9c4a82a9a17cbbf8681bb91a4b61b46f365aeaf%40%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/rbc8492... WEB

https://lists.apache.org/thread.html/rbc84926bacd377503a3f5c37b923c1931f9d343754488d94e6f08039@%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/rbc8492... WEB

https://lists.apache.org/thread.html/rbc84926bacd377503a3f5c37b923c1931f9d343754488d94e6f08039%40%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/raae088... WEB

https://lists.apache.org/thread.html/raae088abdfa4fbd84e1d19d7a7ffe52bf8e426b83e6599ea9a734dba@%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/raae088... WEB

https://lists.apache.org/thread.html/raae088abdfa4fbd84e1d19d7a7ffe52bf8e426b83e6599ea9a734dba%40%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/r770f91... WEB

https://lists.apache.org/thread.html/r770f910653772317b117ab4472b0a32c266ee4abbafda28b8a6f9306@%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/r770f91... WEB

https://lists.apache.org/thread.html/r770f910653772317b117ab4472b0a32c266ee4abbafda28b8a6f9306%40%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/r5df90c... WEB

https://lists.apache.org/thread.html/r5df90c46f7000c4aab246e947f62361ecfb849c5a553dcdb0ef545e1@%3Cissues.cordova.apache.org%3E

lists.apache.org/thread.html/r5df90c... WEB

https://lists.apache.org/thread.html/r5df90c46f7000c4aab246e947f62361ecfb849c5a553dcdb0ef545e1%40%3Cissues.cordova.apache.org%3E

Underscore Release RELEASE

https://github.com/jashkenas/underscore/releases/tag/1.12.1

Underscore Source Repository REPOSITORY

https://github.com/jashkenas/underscore/blob/master/modules/template.js%23L71

Underscore Source Repository REPOSITORY

https://github.com/jashkenas/underscore

seclists.org/fulldisclosure/2025... WEB

http://seclists.org/fulldisclosure/2025/Apr/14

Frequently Asked Questions

What is CVE-2021-23358?

CVE-2021-23358 is a security vulnerability in Underscore involving Arbitrary Code Execution in underscore under CWE-94: Improper Control of Generation of Code ('Code Injection').

Which Underscore versions are affected?

Affected versions include releases prior to 1.12.1 across affected packages: underscore.

What version fixes CVE-2021-23358?

Upgrading to 1.12.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Is underscore affected?

Yes, underscore is affected in releases prior to 1.12.1. Upgrade your dependency to 1.12.1 or later.

What is the CVSS score of CVE-2021-23358?

CVE-2021-23358 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

What CWE is associated with CVE-2021-23358?

CVE-2021-23358 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).

How can I check npm dependencies for CVE-2021-23358?

Run the dependency tree command: 'npm ls underscore'. 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-cf4h-3jhx-xvhq",
  "modified" : "2025-11-04T16:33:59Z",
  "published" : "2021-05-06T16:09:43Z",
  "aliases" : [ "CVE-2021-23358" ],
  "summary" : "Arbitrary Code Execution in underscore",
  "details" : "The package `underscore` from 1.13.0-0 and before 1.13.0-2, from 1.3.2 and before 1.12.1 are vulnerable to Arbitrary Code Execution via the template function, particularly when a variable property is passed as an argument as it is not sanitized.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "underscore"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.3.2"
      }, {
        "fixed" : "1.12.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-23358"
  }, {
    "type" : "WEB",
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  }, {
    "type" : "WEB",
    "url" : "https://github.com/jashkenas/underscore/commit/4c73526d43838ad6ab43a6134728776632adeb66"
  }, {
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    "url" : "https://www.tenable.com/security/tns-2021-14"
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  }, {
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  }, {
    "type" : "WEB",
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    "url" : "https://security.netapp.com/advisory/ntap-20241108-0002"
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  }, {
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  }, {
    "type" : "WEB",
    "url" : "https://lists.debian.org/debian-lts-announce/2021/03/msg00038.html"
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  }, {
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  }, {
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  }, {
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    "type" : "WEB",
    "url" : "http://seclists.org/fulldisclosure/2025/Apr/14"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-03-31T21:59:00Z",
    "nvd_published_at" : "2021-03-29T14:15:00Z"
  }
}

CVSS V3

9.8 CRITICAL

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 High (C:H)

Integrity High (I:H)

Availability High (A:H)

Vector String

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

Advisory Metadata

Source ID: GHSA-cf4h-3jhx-xvhq
Schema Version: 1.4.0
Published: 2021-05-06 16:09
Last Modified: 2025-11-04 16:33
Database Record File: advisories/github-reviewed/2021/05/GHSA-cf4h-3jhx-xvhq/GHSA-cf4h-3jhx-xvhq.json