Medium
PostCSS has XSS via Unescaped in its CSS Stringify Output
Type: advisorySources: OSV
PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Versions prior to 8.5.10 do not escape `` sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML `` in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-41305
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 20:05 UTC · Revision 1
Source evidence
PostCSS has XSS via Unescaped in its CSS Stringify Output
core-osv · Original sourcePublished 24 Apr 2026, 02:27 UTC
PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Versions prior to 8.5.10 do not escape `` sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML `` in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.
osv:CVE-2026-41305
Complete source record
{
"id": "2f1015e48a0ce75a4078d3392936dfe4375f323292a435b220788146dac836d2",
"url": "https://osv.dev/vulnerability/CVE-2026-41305",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "PostCSS has XSS via Unescaped in its CSS Stringify Output",
"summary": "PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Versions prior to 8.5.10 do not escape `` sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML `` in CSS values breaks out of the style context, enabling XSS. Version 8.5.10 fixes the issue.",
"evidence": "osv:CVE-2026-41305",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-41305",
"aliases": [
"CVE-2026-41305",
"GHSA-qx2v-qp2m-jg93"
],
"metrics": [
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"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
}
],
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],
"modified": "2026-10-28T02:30:23.160439524Z",
"provider": "osv",
"references": [
"https://github.com/postcss/postcss/releases/tag/8.5.10",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41305.json",
"https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93",
"https://nvd.nist.gov/vuln/detail/CVE-2026-41305"
],
"provider_metadata": {
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}
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"source_id": "core-osv",
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"published_at": "2026-04-24T02:27:47.719+00:00"
}