This vulnerability allows remote attackers to execute arbitrary code on affected installations of Horde Groupware Webmail Edition. Authentication is required to exploit this vulnerability. The specific flaw exists within Mnemo.php. When parsing the display_notepads parameter, the process does not properly validate user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the www-data user.