Vulnerability Description
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 20.14.6, Happy DOM's CookieContainer in src/cookie/CookieContainer.ts does not correctly validate or match Domain cookie attributes. It can accept a Domain unrelated to the origin setting the cookie, including a public suffix, and separately treats an unrelated suffix-sharing hostname as a match because cookieMatchesURL does not enforce a DNS-label boundary. In server-side rendering and prerendering applications that contact attacker-controlled origins and then make requests to a victim origin, these behaviors can plant and deliver a forged cookie, enabling cookie injection or session fixation. This issue is fixed in version 20.14.6.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05de
- https://github.com/capricorn86/happy-dom/pull/2477
- https://github.com/capricorn86/happy-dom/releases/tag/v20.14.6
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr
FAQ
What is CVE-2026-118661?
CVE-2026-118661 is a vulnerability with a CVSS score of 6.5 (MEDIUM). Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 20.14.6, Happy DOM's CookieContainer in src/cookie/CookieContainer.ts does not correctly valida...
How severe is CVE-2026-118661?
CVE-2026-118661 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-118661?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.