A certain Red Hat patch for SquirrelMail 1.4.8 sets the same SQMSESSID cookie value for all sessions, which allows remote authenticated users to access other users' folder lists and configuration data in opportunistic circumstances by using the standard webmail.php interface. NOTE: this vulnerability exists because of an incorrect fix for CVE-2008-3663.
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.