Headline
CVE-2023-38500: By-passing Cross-Site Scripting Protection in HTML Sanitizer
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.
CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C (4.4)
Problem
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.
Solution
Update to typo3/html-sanitizer versions 1.5.1 or 2.1.2 that fix the problem described.
Credits
Thanks to David Klein and Yaniv Nizry who reported this issue, and to TYPO3 security team members Oliver Hader and Benjamin Franzke who fixed the issue.
References
- TYPO3-CORE-SA-2023-002
Related news
> ### CVSS: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C` (4.4) ### Problem 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`](https://packagist.org/packages/typo3/html-sanitizer). ### Solution Update to `typo3/html-sanitizer` versions 1.5.1 or 2.1.2 that fix the problem described. ### Credits Thanks to David Klein and Yaniv Nizry who reported this issue, and to TYPO3 security team members Oliver Hader and Benjamin Franzke who fixed the issue. ### References * [TYPO3-CORE-SA-2023-002](https://typo3.org/security/advisory/typo3-core-sa-2023-002)