Tina: Broken Access Control: arbitrary bucket-key write/delete in `next-tinacms-s3` (and sibling production media adapters)

Summary The production media handler shipped by next-tinacms-s3 createMediaHandler in packages/next-tinacms-s3/src/handlers.ts accepts an attacker-chosen ?key= query parameter and returns an AWS-signed PutObject URL whose Key is that value, with no check that the key falls under the operator's...