TYPO3 is an open source PHP based web content management system released under the GNU GPL. In affected versions the login screen of the standalone install tool discloses the full path of the transient data directory (e.g. /var/www/html/var/transient/). This applies to composer-based scenarios only - “classic” non-composer installations are not affected. This issue has been addressed in version 12.4.8. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Information Disclosure in typo3/cms-install tool