Parse Server 9.0.0 before 9.10.4-alpha.4 Unauthenticated Class Schema Deletion on MongoDB

Parse Server before 8.6.101 and 9.0.0 before 9.10.4-alpha.4 contains a missing authorization vulnerability on MongoDB deployments that lets clients without the master key delete the stored schema of any class. Unauthenticated attackers can send REST API delete requests targeting the internal _SCHEMA collection to remove field definitions, class-level permissions, and protected fields, exposing data to unauthorized reads and modifications.