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

{
  "id": "d7d19d0beedddb97c935689e832c43a489f90d7f9c67e4c7baa150977efb8b0f",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-118661",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Happy DOM: Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies",
    "summary": "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.",
    "evidence": "cve:CVE-2026-118661",
    "products": [
      {
        "name": {
          "value": "happy-dom",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-118661",
      "aliases": [
        "CVE-2026-118661"
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 6.5,
            "attackVector": "NETWORK",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
            "integrityImpact": "LOW",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "LOW"
          }
        }
      ],
      "affected": [
        {
          "vendor": "capricorn86",
          "product": "happy-dom",
          "versions": [
            {
              "status": "affected",
              "version": "< 20.14.6"
            }
          ]
        }
      ],
      "modified": "2026-10-28T20:30:23.868Z",
      "provider": "cve",
      "references": [
        "https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr",
        "https://github.com/capricorn86/happy-dom/pull/2477",
        "https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05def4e0f2b3",
        "https://github.com/capricorn86/happy-dom/releases/tag/v20.14.6"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-28T20:30:23.868Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-118661",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 486263,
  "published_at": "2026-10-28T20:30:23.868+00:00"
}