---
id: CVE-2026-118660
title: 'Happy DOM: SSRF via iframe and link stylesheet when parsing untrusted HTML'
summary: >-
  Happy DOM is a JavaScript implementation of a web browser without its
  graphical user interface. Prior to 21.0.0, Happy DOM loads iframe src URLs and
  link rel="stylesheet" href URLs by default while parsing untrusted HTML on the
  server be…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-918
vendor: capricorn86
product: happy-dom
affected:
  - happy-dom < 21.0.0
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-29T15:43:35.972529Z'
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T17:23:32.163Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118660'
references:
  - url: >-
      https://github.com/capricorn86/happy-dom/security/advisories/GHSA-c8p4-j97h-3vg8
    label: >-
      https://github.com/capricorn86/happy-dom/security/advisories/GHSA-c8p4-j97h-3vg8
  - url: 'https://github.com/capricorn86/happy-dom/pull/2502'
    label: 'https://github.com/capricorn86/happy-dom/pull/2502'
  - url: >-
      https://github.com/capricorn86/happy-dom/commit/0a99c7525a1d0043e3182843ae33466ab7b19e74
    label: >-
      https://github.com/capricorn86/happy-dom/commit/0a99c7525a1d0043e3182843ae33466ab7b19e74
  - url: 'https://github.com/capricorn86/happy-dom/releases/tag/v21.0.0'
    label: 'https://github.com/capricorn86/happy-dom/releases/tag/v21.0.0'
  - url: 'https://github.com/advisories/GHSA-c8p4-j97h-3vg8'
tags:
  - cve.org
  - ghsa
  - npm
aliases:
  - GHSA-c8p4-j97h-3vg8
ecosystem: npm
patched:
  - happy-dom 21.0.0
epss: 0.00405
epssPercentile: 0.34894
ingestedAt: '2026-10-28T21:18:49.943Z'
---

## Overview

Happy DOM is a JavaScript implementation of a web browser without its graphical user interface. Prior to 21.0.0, Happy DOM loads iframe src URLs and link rel="stylesheet" href URLs by default while parsing untrusted HTML on the server because disableIframePageLoading and disableCSSFileLoading default to false. An attacker who controls parsed HTML can therefore cause server-side requests to arbitrary internal or cloud endpoints without an application opt-in and may expose confidential responses or credentials returned by those endpoints. This issue is fixed in version 21.0.0.

## Affected

- `happy-dom < 21.0.0`

## Remediation

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

## Package advisory (CVE-2026-118660)

Affected packages:

- `happy-dom <= 20.14.6`

Patched in:

- `happy-dom 21.0.0`

Source: https://github.com/advisories/GHSA-c8p4-j97h-3vg8