TYPO3 is a free and open source Content Management Framework. Backend users could see items in the backend page tree without having access if the mounts pointed to pages restricted for their user/group, or if no mounts were configured but the pages allowed access to "everybody." However, affected users could not manipulate these pages. Users are advised to update to TYPO3 versions 10.4.46 ELTS, 11.5.40 LTS, 12.4.21 LTS, 13.3.1 that fix the problem described. There are no known workarounds for this vulnerability.
https://typo3.org/security/advisory/typo3-core-sa-2024-012
https://github.com/TYPO3/typo3/security/advisories/GHSA-rf5m-h8q9-9w6q