What the vulnerability does
Description
By exploiting the defVals parameter, attackers could bypass field‑level access checks during record creation in the TYPO3 backend. This gave them the ability to insert arbitrary data into prohibited exclude fields of a database table for which the user already has write permission for a reduced set of fields. This issue affects TYPO3 CMS versions 10.0.0-10.4.54, 11.0.0-11.5.48, 12.0.0-12.4.40, 13.0.0-13.4.22 and 14.0.0-14.0.1.
