Nextcloud Deck is a Kanban-style project & personal management tool for Nextcloud. In versions prior to 1.4.8, 1.5.6, and 1.6.1, an authenticated user can move stacks with cards from their own board to a board of another user. The Nextcloud Deck app contains a patch for this issue in versions 1.4.8, 1.5.6, and 1.6.1. There are no known currently-known workarounds available.