---
id: CVE-2026-47345
aliases:
  - GHSA-p5j5-4j3q-8mq8
title: TYPO3 HTML Sanitizer allows Cross-site Scripting
summary: TYPO3 HTML Sanitizer allows Cross-site Scripting
severity: medium
cwe:
  - CWE-79
vendor: typo3
product: typo3/html-sanitizer
ecosystem: composer
affected:
  - typo3/html-sanitizer < 2.3.2
patched:
  - typo3/html-sanitizer 2.3.2
published: '2026-06-12'
updated: '2026-06-12'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-p5j5-4j3q-8mq8'
references:
  - url: >-
      https://github.com/TYPO3/html-sanitizer/security/advisories/GHSA-p5j5-4j3q-8mq8
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-47345'
  - url: >-
      https://github.com/TYPO3/html-sanitizer/commit/8b5d0be44ded457ca993ec9ca93d859941c63764
  - url: >-
      https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/html-sanitizer/CVE-2026-47345.yaml
  - url: 'https://typo3.org/security/advisory/typo3-core-sa-2026-006'
  - url: 'https://github.com/advisories/GHSA-p5j5-4j3q-8mq8'
tags:
  - ghsa
  - composer
epss: 0.00437
epssPercentile: 0.35296
ingestedAt: '2026-07-07T15:41:59.017Z'
---

## Overview

Namespace attributes are not encoded correctly during HTML serialization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2.

Credits to Doyensec in collaboration with Claude and Anthropic Research for reporting this vulnerability.

## Affected packages

- `typo3/html-sanitizer < 2.3.2`

## Remediation

Upgrade to a patched release:

- `typo3/html-sanitizer 2.3.2`