{"id":"CVE-2026-118661","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-118661","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…","details":"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.","published":"2026-10-28T21:16:56.267","modified":"2026-10-28T21:16:56.267","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05def4e0f2b3","label":"capricorn86/happy-dom@f21dbd7"},"references":[{"type":"WEB","url":"https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05def4e0f2b3"},{"type":"WEB","url":"https://github.com/capricorn86/happy-dom/pull/2477"},{"type":"WEB","url":"https://github.com/capricorn86/happy-dom/releases/tag/v20.14.6"},{"type":"WEB","url":"https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T21:16:56.267"}}