MongoDB Server 9.0: a user with basic read/write rights can read collections they lack access to through a view

An authorization weakness in the aggregation framework of MongoDB Server may allow an authenticated user holding only basic database privileges to read the contents of collections in a database for which they have not been granted read access. The privilege evaluation performed while a view definition is validated does not cover a nested portion of the supplied pipeline, so the resulting view returns data the user is otherwise refused. This may result in unintended access to data, including stored authentication material.