CVE-2026-47345 TYPO3 HTML Sanitizer allows Cross-Site Scripting
An attacker can bypass XSS prevention in the TYPO3 HTML Sanitizer library by exploiting incorrect namespace attribute encoding during serialization.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-47345?
CVE-2026-47345 is a medium-severity cross-site scripting vulnerability in TYPO3 HTML Sanitizer, published on 8 Jun 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-47345?
2 open source packages ship an affected version, including typo3/html-sanitizer.
| Package | Affected | Fixed in |
|---|---|---|
typo3/html-sanitizer Packagist | All versions | 2.3.2 |
typo3/html-sanitizer Packagist | All versions | 2.3.2 |
How do I fix CVE-2026-47345?
Upgrade typo3/html-sanitizer to 2.3.2 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-47345 being exploited?
There is no known exploitation of CVE-2026-47345 in the wild and no public exploit code.
Sources
Also known as GHSA-p5j5-4j3q-8mq8.