---
id: CVE-2026-118659
title: >-
  @happy-dom/server-renderer: ServerRendererServer Target-Origin Bypass SSRF /
  Open Proxy
summary: >-
  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-c…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-918
vendor: capricorn86
product: happy-dom
affected:
  - happy-dom < 21.0.2
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-29T18:27:17.941408Z'
exploitAvailable: true
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T18:27:45.701Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118659'
references:
  - url: >-
      https://github.com/capricorn86/happy-dom/security/advisories/GHSA-pmf4-3xr3-xjhg
    label: >-
      https://github.com/capricorn86/happy-dom/security/advisories/GHSA-pmf4-3xr3-xjhg
  - url: 'https://github.com/capricorn86/happy-dom/pull/2520'
    label: 'https://github.com/capricorn86/happy-dom/pull/2520'
  - url: >-
      https://github.com/capricorn86/happy-dom/commit/1f3ffdf634231361de1a2acb629b4fe8ee1bd85d
    label: >-
      https://github.com/capricorn86/happy-dom/commit/1f3ffdf634231361de1a2acb629b4fe8ee1bd85d
  - url: 'https://github.com/capricorn86/happy-dom/releases/tag/v21.0.2'
    label: 'https://github.com/capricorn86/happy-dom/releases/tag/v21.0.2'
tags:
  - cve.org
  - exploit-available
epss: 0.0039
epssPercentile: 0.33155
ingestedAt: '2026-11-01T23:03:55.421Z'
---

## Overview

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.

## Affected

- `happy-dom < 21.0.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.