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 `</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. Version 8.5.10 fixes the issue.
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Fri, 24 Apr 2026 02:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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 `</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. Version 8.5.10 fixes the issue. | |
| Title | PostCSS has XSS via Unescaped </style> in its CSS Stringify Output | |
| Weaknesses | CWE-79 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-04-24T02:27:47.719Z
Reserved: 2026-04-20T14:01:46.670Z
Link: CVE-2026-41305
No data.
Status : Received
Published: 2026-04-24T03:16:11.547
Modified: 2026-04-24T03:16:11.547
Link: CVE-2026-41305
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OpenCVE Enrichment
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Weaknesses