compose.php in SquirrelMail 1.4.22 calls unserialize for the $mailtodata value, which originates from an HTTP GET request. This is related to mailto.php.

compose.php in SquirrelMail 1.4.22 calls unserialize for the $attachments value, which originates from an HTTP POST request. NOTE: the vendor disputes this because these two conditions for PHP object injection are not satisfied: existence of a PHP magic method (such as __wakeup or __destruct), and any attack-relevant classes must be declared before unserialize is called (or must be autoloaded).

XSS was discovered in SquirrelMail through 1.4.22 and 1.5.x through 1.5.2. Due to improper handling of RCDATA and RAWTEXT type elements, the built-in sanitization mechanism can be bypassed. Malicious script content from HTML e-mail can be executed within the application context via crafted use of (for example) a NOEMBED, NOFRAMES, NOSCRIPT, or TEXTAREA element.

The mail message display page in SquirrelMail through 1.4.22 has XSS via the formaction attribute.

The mail message display page in SquirrelMail through 1.4.22 has XSS via SVG animations (animate to attribute).

The mail message display page in SquirrelMail through 1.4.22 has XSS via a "<form action='data:text" attack.

The mail message display page in SquirrelMail through 1.4.22 has XSS via a "<svg><a xlink:href=" attack.

The mail message display page in SquirrelMail through 1.4.22 has XSS via a "<math><maction xlink:href=" attack.

The mail message display page in SquirrelMail through 1.4.22 has XSS via a "<math xlink:href=" attack.

A directory traversal flaw in SquirrelMail 1.4.22 allows an authenticated attacker to exfiltrate (or potentially delete) files from the hosting server, related to ../ in the att_local_name field in Deliver.class.php.