How can the storage location of session data impact the reliability of sessions in PHP on shared hosting environments?

When session data is stored on the server in a shared hosting environment, it can be accessed by other users on the same server, potentially leading to security risks and data leakage. To ensure the reliability of sessions in PHP on shared hosting environments, it is recommended to store session data in a secure and isolated location, such as a database or a custom directory outside of the web root.

// Set session save path to a custom directory outside of the web root
session_save_path('/path/to/custom/session/directory');