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.

Squirrelmail 1.4.15 does not set the secure flag for the session cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.