functions/imap_general.php in SquirrelMail as used in Red Hat Enterprise Linux (RHEL) 4 and 5 does not properly handle 8-bit characters in passwords which allows remote attackers to cause a denial of service (disk consumption) by making many IMAP login attempts with different usernames leading to the creation of many preference files. NOTE: this issue exists because of an incorrect fix for CVE-2010-2813.