Session fixation exists in ZoneMinder through 1.32.3, as an attacker can fixate his own session cookies to the next logged-in user, thereby hijacking the victim's account. This occurs because a set of multiple cookies (between 3 and 5) is being generated when a user successfully logs in, and these sets overlap for successive logins.
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.