SquirrelMail is a standards-based webmail package written in PHP. A cross-site scripting flaw was found in the way SquirrelMail performed the sanitization of HTML style tag content. A remote attacker could use this flaw to send a specially-crafted Multipurpose Internet Mail Extensions message that, when opened by a victim, would lead to arbitrary web script execution in the context of their SquirrelMail session. Multiple cross-site scripting flaws were found in SquirrelMail. A remote attacker could possibly use these flaws to execute arbitrary web script in the context of a victim"s SquirrelMail session. An input sanitization flaw was found in the way SquirrelMail handled the content of various HTML input fields. A remote attacker could use this flaw to alter user preference values via a newline character contained in the input for these fields. It was found that the SquirrelMail Empty Trash and Index Order pages did not protect against Cross-Site Request Forgery attacks. If a remote attacker could trick a user, who was logged into SquirrelMail, into visiting a specially-crafted URL, the attacker could empty the victim"s trash folder or alter the ordering of the columns on the message index page. SquirrelMail was allowed to be loaded into an HTML sub-frame, allowing a remote attacker to perform a clickjacking attack against logged in users and possibly gain access to sensitive user data. With this update, the SquirrelMail main frame can only be loaded into the top most browser frame. A flaw was found in the way SquirrelMail handled failed log in attempts. A user preference file was created when attempting to log in with a password containing an 8-bit character, even if the username was not valid. A remote attacker could use this flaw to eventually consume all hard disk space on the target SquirrelMail server. A flaw was found in the SquirrelMail Mail Fetch plug-in. If an administrator enabled this plug-in, a SquirrelMail user could use this flaw to port scan the local network the server was on. Users of SquirrelMail should upgrade to this updated package, which contains backported patches to correct these issues.