An issue was discovered in Serenity Serene (and StartSharp) before 6.7.0. When a password reset request occurs, the server response leaks the existence of users. If one tries to reset a password of a non-existent user, an error message indicates that this user does not exist.
https://seclists.org/fulldisclosure/2023/May/14
https://github.com/serenity-is/Serenity/commit/11b9d267f840513d04b4f4d4876de7823a6e48d2