Information disclosure in Ladybirdbrowser Ladybird
CVE-2026-119331
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.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Ladybirdbrowser Ladybird — versions < c0d68bddf3e3616e5173835f0f4c155ee9700d91
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-119331?
- CVE-2026-119331 is a high-severity vulnerability in Ladybirdbrowser Ladybird, classified under Information Disclosure. CVSS score: 7.1/10. Published 2026-10-30.
- How severe is CVE-2026-119331?
- High severity. CVSS v3 base score is 7.1 out of 10.