TYPO3-CORE-SA-2023-007: By-passing Cross-Site Scripting Protection in HTML Sanitizer

Categories: Development, TYPO3 CMS Created by Oliver Hader
It has been discovered that TYPO3 CMS is vulnerable to cross-site scripting.

Problem Description

DOM processing instructions are not handled correctly. This allows bypassing the cross-site scripting mechanism of typo3/html-sanitizer.


Update to TYPO3 versions 8.7.55 ELTS, 9.5.44 ELTS, 10.4.41 ELTS, 11.5.33, 12.4.8 that fix the problem described above.


Thanks to Yaniv Nizry and Niels Dossche who reported this issue, and to TYPO3 core & security team member Oliver Hader who fixed the issue.

General Advice

Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.

General Note

All security related code changes are tagged so that you can easily look them up in our review system.