CVE-2026-41305
PostCSS has XSS via Unescaped </style> in its CSS Stringify Output
6.1
MEDIUM
CVSS 3.1
EPSS 0.01%
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.
How to fix CVE-2026-41305
To remediate CVE-2026-41305, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 8.5.10 or later
Is CVE-2026-41305 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 8.5.10
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |