The Community Edition version 9.0 of OS4ED's openSIS Classic has a broken access control vulnerability in the database backup functionality. Whenever an admin generates a database backup, the backup is stored in the web root while the file name has a format of "opensisBackup<date>.sql" (e.g. "opensisBackup07-20-2023.sql"), i.e. can easily be guessed. This file can be accessed by any unauthenticated actor and contains a dump of the whole database including password hashes.