Nextcloud: Nextcloud Deck : Possibility for anyone to add a stack with existing tasks on anyone's board

Hi everyone, Hope you are well ! I found an IDOR vulnerability, allowing any user without privilege to add lists with tasks in any user board. This was tested on a Nextcloud Hub II server v23 with the Deck application in version 1.6.0. Steps To Reproduce: Beforehand: - Have an A user with a board...