CVE-2026-41305: Postcss

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Postcss Postcss: before 8.5.10 (fixed in 8.5.10)

Published 2026-04-24. Last modified 2026-06-17.