What are the potential security risks when using PHP sessions for user authentication?

One potential security risk when using PHP sessions for user authentication is session hijacking, where an attacker steals the session ID and impersonates the user. To mitigate this risk, it is important to regenerate the session ID after a successful login or privilege change. This helps prevent session fixation attacks and makes it harder for attackers to hijack sessions.

// Regenerate session ID after successful login or privilege change
session_regenerate_id(true);