Vulnerability Description
Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HTTP/2 requests and resolves attacker-controlled :path values against server.targetOrigin in #onIncomingRequest in packages/@happy-dom/server-renderer/src/ServerRendererServer.ts without confirming that the resolved origin remains trusted before calling fetch. A protocol-relative path can change the destination to an arbitrary HTTP or HTTPS endpoint reachable by the server, including local and internal services, and the proxy relays the fetched response headers and body to the requester. This issue is fixed in version 21.0.2.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/capricorn86/happy-dom/commit/1f3ffdf634231361de1a2acb629b4fe8
- https://github.com/capricorn86/happy-dom/pull/2520
- https://github.com/capricorn86/happy-dom/releases/tag/v21.0.2
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-pmf4-3xr3-xjhg
- https://github.com/capricorn86/happy-dom/security/advisories/GHSA-pmf4-3xr3-xjhg
FAQ
What is CVE-2026-118659?
CVE-2026-118659 is a vulnerability with a CVSS score of 7.5 (HIGH). Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.2, the Happy DOM server-renderer package's ServerRendererServer accepts unauthenticated HT...
How severe is CVE-2026-118659?
CVE-2026-118659 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-118659?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.