The SecurityAgent component in Mac OS X 10.4 through 10.4.10 allows attackers with physical access to bypass the authentication dialog of the screen saver and send keystrokes to a process, related to "handling of keyboard focus between secure text fields."
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.