CVE-2026-118661
Happy DOM: Cookie scope forgery: no DNS-label boundary on Domain= matching , attacker origin sets victim cookies
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.
Fixes and workarounds
Fix
happy-dom (npm): OSV reports a fixed version 20.14.6. Check the advisory for supported release branches.
Source: OSV GHSA-5fpq-26gf-qwcrAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| happy-dom capricorn86 |
< 20.14.6 (affected) | CNA: GitHub_M |
happy-domhappy-dom
npm |
≥ 0; < 20.14.6 (affected, semver); OSV events: introduced 0; fixed 20.14.6Source events (semver)Other versions: unaffected |
OSV GHSA-5fpq-26gf-qwcr |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 6.5 medium |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N | CNA: GitHub_M |
Exploit evidence
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcr
exploit · ADP: CISA-ADP
References
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcrCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/capricorn86/happy-dom/pull/2477CNA: GitHub_M · x_refsource_MISC
- https://github.com/capricorn86/happy-dom/commit/f21dbd7d0a0c63cdd41954ba5d0f05def4e0f2b3CNA: GitHub_M · x_refsource_MISC
- https://github.com/capricorn86/happy-dom/releases/tag/v20.14.6CNA: GitHub_M · x_refsource_MISC
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-5fpq-26gf-qwcrADP: CISA-ADP · exploit
- https://github.com/advisories/GHSA-5fpq-26gf-qwcrOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-5fpq-26gf-qwcrOSV / GitHub Security Advisories · osv
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