---
id: CVE-2026-65902
title: DOMPurify before 3.4.7 Hook Mutation Pollution via allowedTags
summary: >-
  DOMPurify before 3.4.7 passes direct references to the module-level
  DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement
  and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes
  when sanitize…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-501
vendor: cure53
product: DOMPurify
affected:
  - DOMPurify < 3.4.7
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-07-23T13:58:18.807154Z'
exploitAvailable: true
published: '2026-07-23'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T21:16:29.413Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-65902'
references:
  - url: >-
      https://github.com/cure53/DOMPurify/security/advisories/GHSA-76mc-f452-cxcm
    label: GitHub Security Advisory (GHSA-76mc-f452-cxcm)
  - url: >-
      https://github.com/cure53/DOMPurify/commit/7996f1dc78eb8b7922388aed75d94a9f8fad9a36
    label: Patch Commit
  - url: >-
      https://www.vulncheck.com/advisories/dompurify-before-hook-mutation-pollution-via-allowedtags
    label: >-
      VulnCheck Advisory: DOMPurify before 3.4.7 Hook Mutation Pollution via
      allowedTags
tags:
  - cve.org
  - exploit-available
epss: 0.00355
epssPercentile: 0.2946
ingestedAt: '2026-11-03T08:39:35.583Z'
---

## Overview

DOMPurify before 3.4.7 passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes when sanitize is called without an explicit cfg.ALLOWED_TAGS / cfg.ALLOWED_ATTR array. A hook that mutates these fields permanently widens the default allow-lists for the lifetime of the DOMPurify instance, so all subsequent default-config sanitize calls inherit the widened defaults and attacker payloads using the poisoned tag/attribute name survive sanitization. removeAllHooks(), clearConfig(), and passing a fresh cfg do not recover the state; only constructing a new DOMPurify instance does.

## Affected

- `DOMPurify < 3.4.7`

## Remediation

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