cssnano is a popular npm package designed to minify CSS code, built upon the PostCSS ecosystem to deliver a modular and efficient minification process. Comparing versions 1.2.0 and 1.1.0 reveals a few key updates beneficial for developers.
Both versions maintain the same core structure, description, development dependencies and licensing (MIT). However, a notable difference lies in the dependencies, specifically postcss-merge-rules. Version 1.2.0 upgrades this dependency to version 1.3.0, while version 1.1.0 uses version 1.2.2. This update likely incorporates bug fixes, performance improvements, or new features related to merging CSS rulesets more effectively, leading to better minification results. Another small update is in the postcss-merge-idents dependency, upgraded from 1.0.0 to 1.0.1. These small dependency tweaks can improve the efficiency and effectiveness of CSS minification.
Developers choosing between these versions should prioritize 1.2.0 for its potentially enhanced rule merging capabilities and improvements stemming from dependency updates. Using the latest minor version enables better compatibility with newer CSS standards and potentially resolves previously existing bugs; the upgrade to the newest version of the dependency packages ensures code stability and access to current optimization algorithms. Both versions provide robust CSS minification, thus optimizing front-end delivery for faster loading times.
All the vulnerabilities related to the version 1.2.0 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.