Flask-AppBuilder versions before 4.3.0 lack rate limiting which can allow an attacker to brute-force user credentials. Version 4.3.0 includes the ability to enable rate limiting using `AUTH_RATE_LIMITED = True`, `RATELIMIT_ENABLED = True`, and setting an `AUTH_RATE_LIMIT`.
https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-9hcr-9hcv-x6pv
https://flask-limiter.readthedocs.io/en/stable/configuration.html