CVE-2026-41305

MEDIUM

6.1

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.

CVE Details

CVSS v3.1 Score6.1

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

Published4/24/2026

Last Modified4/24/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-79

References

https://github.com/postcss/postcss/releases/tag/8.5.10(security-advisories@github.com)

https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93(security-advisories@github.com)

https://github.com/postcss/postcss/security/advisories/GHSA-qx2v-qp2m-jg93(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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