Hello everyone,
I've noticed that Dovecot 2.3.20-4 segfaults when a user tries to log in and that users' password is hashed as yescrypt in /etc/shadow. No issues with SHA512 hashing.
It started to happen after this change and on a new install:make_clickable_callback(MAGIC_URL_FULL, ' ', 'https://archlinux.org/news/changes-to-default-password-hashing-algorithm-and-umask-settings/', '', ' class="postlink"')
A simple fix is to adjust "ENCRYPT_METHOD YESCRYPT" to "ENCRYPT_METHOD SHA512" and let the user re-enter a new password.