---
id: CVE-2026-119331
title: >-
  Ladybird: Missing origin-clean enforcement in CSSStyleSheet allows
  cross-origin CSS read and mutation
summary: >-
  Ladybird is a truly independent web browser. Prior to the
  c0d68bddf3e3616e5173835f0f4c155ee9700d91 commit, CSSStyleSheet.cssRules,
  insertRule(), and deleteRule() in Libraries/LibWeb/CSS/CSSStyleSheet.cpp did
  not enforce the stylesheet or…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-200
  - CWE-346
vendor: LadybirdBrowser
product: ladybird
affected:
  - ladybird < c0d68bddf3e3616e5173835f0f4c155ee9700d91
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-30T21:18:16.293042Z'
published: '2026-10-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T22:14:59.829Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-119331'
references:
  - url: >-
      https://github.com/LadybirdBrowser/ladybird/security/advisories/GHSA-xj66-c4cw-xwh3
    label: >-
      https://github.com/LadybirdBrowser/ladybird/security/advisories/GHSA-xj66-c4cw-xwh3
  - url: >-
      https://github.com/LadybirdBrowser/ladybird/commit/c0d68bddf3e3616e5173835f0f4c155ee9700d91
    label: >-
      https://github.com/LadybirdBrowser/ladybird/commit/c0d68bddf3e3616e5173835f0f4c155ee9700d91
tags:
  - cve.org
epss: 0.00183
epssPercentile: 0.07973
ingestedAt: '2026-11-05T16:24:31.476Z'
---

## Overview

Ladybird is a truly independent web browser. Prior to the c0d68bddf3e3616e5173835f0f4c155ee9700d91 commit, CSSStyleSheet.cssRules, insertRule(), and deleteRule() in Libraries/LibWeb/CSS/CSSStyleSheet.cpp did not enforce the stylesheet origin-clean flag with the required SecurityError, even though cross-origin imported stylesheets were correctly marked non-origin-clean. A malicious page could read parsed rules from a stylesheet loaded without CORS and could insert or delete rules in the victim stylesheet, bypassing the Same-Origin Policy. Reading could expose selectors, generated content, feature markers, or other sensitive rule text, while mutation could alter page visibility or layout. The issue does not provide memory corruption, code execution, or persistence after the attacker page closes. This vulnerability is fixed by commit c0d68bddf3e3616e5173835f0f4c155ee9700d91.

## Affected

- `ladybird < c0d68bddf3e3616e5173835f0f4c155ee9700d91`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.