Bug 2563189 (CVE-2026-118661)

Summary:	CVE-2026-118661 happy-dom: happy-dom: Cookie injection via improper cookie domain validation
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	doconnor, dschmidt, jlanda, kshier, rbobbitt, simaishi, stcannon, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in happy-dom. The cookie management component fails to properly validate and match domain attributes, allowing it to accept cookies for unrelated domains and match hostnames without enforcing domain boundaries. In server-side rendering environments, a remote attacker controlling a malicious origin can plant forged cookies that are subsequently sent to victim domains. This flaw can enable cookie injection and session fixation, potentially compromising user sessions.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2563387, 2563388, 2563389
Bug Blocks:

Description OSIDB Bzimport 2026-10-28 20:42:06 UTC

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.