GHSA-9xh7-5jg8-mf43: Vikunja before 2.7.1 Improper Authorization in Kanban Bucket Deletion

Vikunja before 2.7.1 contains an improper authorization vulnerability in canDoBucket that allows users with project write access to delete buckets via a mismatched view ID. Attackers can request deletion through another view's bucket endpoint to bypass the last-bucket rule, leaving dangling default/done bucket references and inconsistent task buckets.