---
id: GHSA-jxrp-r7gx-q4j8
title: >-
  Duplicate Advisory: DOMPurify: `CUSTOM_ELEMENT_HANDLING` bypasses
  `afterSanitizeElements` for allowed custom elements.
summary: >-
  Duplicate Advisory: DOMPurify: `CUSTOM_ELEMENT_HANDLING` bypasses
  `afterSanitizeElements` for allowed custom elements.
severity: medium
cvss: 6.1
cwe:
  - CWE-79
vendor: dompurify
product: dompurify
ecosystem: npm
affected:
  - dompurify <= 3.4.11
published: '2026-07-24'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T22:43:13Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-jxrp-r7gx-q4j8'
references:
  - url: >-
      https://github.com/cure53/DOMPurify/security/advisories/GHSA-c2j3-45gr-mqc4
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-66010'
  - url: >-
      https://www.vulncheck.com/advisories/dompurify-before-hook-bypass-via-custom-element-handling
  - url: 'https://github.com/advisories/GHSA-jxrp-r7gx-q4j8'
tags:
  - ghsa
  - npm
ingestedAt: '2026-10-02T23:34:57.401Z'
---

## Overview

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-c2j3-45gr-mqc4. This link is maintained to preserve external references.

## Original Description

DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.

## Affected packages

- `dompurify <= 3.4.11`

## Remediation

Refer to the advisory for the patched release.