After installing MariaDB on Fedora, the default configuration does not set a password. Specifically, the root user in MariaDB has an empty default password, meaning you can log in to the database as the root user without entering a password.
For security reasons, it is recommended to run the security installation script mysql_secure_installation immediately after installation. This script guides you through setting the root user's password and performing other security-related operations, such as removing anonymous users and the test database, and disabling remote root login.
For example, after installing MariaDB, you can run the security installation script with the following command:
sudo mysql_secure_installation
The script will prompt you to enter the root user's password; since the default password is empty, you can simply press Enter and follow the prompts to set a new password and complete the remaining security configurations.