Canto <= 3.0.4 - Unauthenticated Remote File Inclusion

The Canto plugin for WordPress is vulnerable to Remote File Inclusion in versions up to, and including, 3.0.4 via the 'wp_abspath' parameter. This allows unauthenticated attackers to include and execute arbitrary remote code on the server, provided that allow_url_include is enabled. Local File Inclusion is also possible, albeit less useful because it requires that the attacker be able to upload a malicious php file via FTP or some other means into a directory readable by the web server.