Patch Forecast
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CVE-2026-118659

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface

Risk score
50/100
CVSS
7.5 v3.1
Published
28 Oct 2026

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What to know

What it is
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 packag…
Affected
See advisory
Fix
Upgrade the product to 21.0.2 or later.
Exploitation
No known exploitation

Why it is Yellow

  • CVSS 7.5 high
  • Remotely exploitable without logging in

References

Original 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.

Last activity 28 Oct 2026. Patch Forecast updates every hour.