TYPO3 Core

The usergroup field for a backend user has a DB length of 255 chars. Currently TCA limits the max. amount of groups to assign to a backend user to 20 items. On websites with many (e.g. 500+) backend groups this limit may lead to problems, when a backend user has access to many different areas of the website (e.g. a University website with many subsites) and it is not possible to add more than 20 groups.

Since the varchar(255) DB field can hold a max. of 23 groups (biggest UID = 4294967295, 10 chars length + 1 char for a comma => 255/11 ~ 23 groups), the DB fieldtype should be changed to TEXT if the TCA maxitems value increases.

For fe_users a max of 50 groups per user is configured (fieldtype tinytext - length = 255 chars). This configuration may under very rare conditions not work, if the length of fe_groups UIDs are 10 chars.