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CVE-2026-118661— Happy DOM: Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies

Quick assessment

Affected
capricorn86 happy-dom
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Happy DOM 是一个没有图形用户界面的 Web 浏览器 JavaScript 实现。在 20.14.6 版本之前，位于 的 CookieContainer 未能正确验证或匹配 Cookie 的 Domain 属性。它允许接受与设置 Cookie 的源无关的 Domain，包括公共后缀；同时，由于 未强制实施 DNS 标签边界，它将共享无关后缀的主机名误判为匹配项。在涉及接触攻击者控制的源并随后向受害者源发起请求的服务器端渲染（SSR）和预渲染（prerendering）应用中，这些行为可用于植入并传递伪造的

CVSS 6.5 · Medium

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-118661

Vulnerability Information
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Vulnerability Title
Happy DOM: Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies
Source: CVE Program / CVE List V5
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在信任Cookie未进行验证与完整性检查
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
capricorn86 happy-dom < 20.14.6 -

II. Public POCs for CVE-2026-118661

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III. Intelligence Information for CVE-2026-118661

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Patches & Fixes for CVE-2026-118661 (2)

Vendor Advisories for CVE-2026-118661 (1)

Vendor Pages for CVE-2026-118661 (1)

Same Patch Batch · capricorn86 · 2026-10-28 · 3 CVEs total

CVE-2026-118660 8.6 HIGH Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML
CVE-2026-118659 7.5 HIGH @happy-dom/server-renderer: ServerRendererServer Target-Origin Bypass SSRF / Open Proxy

IV. Related Vulnerabilities

Same product: happy-dom
Same vendor: capricorn86
Same weakness: CWE-565