The FluentBoards WordPress plugin before 2.0.15 does not properly verify that a user holds board-manager privileges before performing several board-management operations, checking only board membership. This allows any member of a board to carry out manager-only actions on it, including adding or removing members and enabling public access to a private board.
https://wpscan.com/vulnerability/07c4ebd6-1cf9-4951-a89b-4288d10b0df1/