Ghost Content API filter bypass reveals private fields

Ghost is a Node.js content management system. From 5.46.1 until 6.21.2, the validation applied to filters on the public API endpoints could be partially bypassed, making it possible to reveal private fields via a brute force attack. If SQLite was used as the database password hashes were fully accessible. If MySQL was used as the database the password hashes' case (uppercase / lowercase) would have been lost, which would likely have rendered a further brute force attack on the discovered hashes fruitless. This vulnerability is fixed in 6.21.2.