CVE-2021-3765: Validator Inefficient Regular Expression Complexity Vulnerability

MODERATE
Advisory Identifier: GHSA-qgmg-gppg-76g5
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CVSS 5.3
CWE-1333
Published
Advisory Summary

CVE-2021-3765 is a MODERATE (CVSS 5.3) inefficient regular expression complexity vulnerability (CWE-1333: Inefficient Regular Expression Complexity) affecting Validator libraries in the npm ecosystem. The issue involves inefficient regular expression complexity in validator.js. Remediation is available by upgrading affected packages to version 13.7.0.

CVE-2021-3765 at a Glance

CVE Identifier CVE-2021-3765
GHSA Identifier GHSA-qgmg-gppg-76g5
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-1333: Inefficient Regular Expression Complexity
Affected Product Validator
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 None (I:N)
Availability Low (A:L)

How to Fix CVE-2021-3765

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

validator fixed: 13.7.0 
npm install validator@13.7.0
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 validator

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2021-3765, inspect your project dependencies using npm:

npm ls validator

Analyze the terminal output to locate any version of Validator in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 13.7.0), your application is affected.

Note: The npm ls validator 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-1333: Inefficient Regular Expression Complexity, where the product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential. In Validator, 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

validator.js prior to 13.7.0 is vulnerable to Inefficient Regular Expression Complexity

CVE-2021-3765 Affected Validator Versions

1 component(s)
Fixed Versions:
13.7.0
Product / Package Ecosystem Affected Versions Fixed Version
validator
npm/validator
npm
< 13.7.0
13.7.0

References

NVD — CVE-2021-3765 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-3765
Security Fix Commit FIX COMMIT
https://github.com/validatorjs/validator.js/commit/496fc8b2a7f5997acaaec33cc44d0b8dba5fb5e1
Validator Source Repository REPOSITORY
https://github.com/validatorjs/validator.js
huntr.dev/bounties/c37e975c-2... WEB
https://huntr.dev/bounties/c37e975c-21a3-4c5f-9b57-04d63b28cfc9

Frequently Asked Questions

What is CVE-2021-3765?
CVE-2021-3765 is a security vulnerability in Validator involving Inefficient Regular Expression Complexity in validator.js under CWE-1333: Inefficient Regular Expression Complexity.
Which Validator versions are affected?
Affected versions include releases prior to 13.7.0 across affected packages: validator.
What version fixes CVE-2021-3765?
Upgrading to 13.7.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is validator affected?
Yes, validator is affected in releases prior to 13.7.0. Upgrade your dependency to 13.7.0 or later.
What is the CVSS score of CVE-2021-3765?
CVE-2021-3765 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2021-3765?
CVE-2021-3765 is classified under CWE-1333: Inefficient Regular Expression Complexity (The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.).
How can I check npm dependencies for CVE-2021-3765?
Run the dependency tree command: 'npm ls validator'. 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-qgmg-gppg-76g5",
  "modified" : "2021-11-03T14:46:00Z",
  "published" : "2021-11-03T17:34:45Z",
  "aliases" : [ "CVE-2021-3765" ],
  "summary" : "Inefficient Regular Expression Complexity in validator.js",
  "details" : "validator.js prior to 13.7.0 is vulnerable to Inefficient Regular Expression Complexity",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "validator"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "13.7.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-3765"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/validatorjs/validator.js/commit/496fc8b2a7f5997acaaec33cc44d0b8dba5fb5e1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/validatorjs/validator.js"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.dev/bounties/c37e975c-21a3-4c5f-9b57-04d63b28cfc9"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-11-03T14:46:00Z",
    "nvd_published_at" : "2021-11-02T07:15:00Z"
  }
}