CVE-2026-41305
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.
- Published Apr 24, 2026
- CVSS 6.1 medium
- 0.3% chance of exploitation in the next 30 days (EPSS)
- A fix is available
Affected software
In the news
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- Multiple vulnerabilities in IBM products CERT-FR ·