Unrestricted file upload vulnerability in the wp_check_filetype function in wp-includes/functions.php in WordPress before 2.8.6, when a certain configuration of the mod_mime module in the Apache HTTP Server is enabled, allows remote authenticated users to execute arbitrary code by posting an attachment with a multiple-extension filename, and then accessing this attachment via a direct request to a wp-content/uploads/ pathname, as demonstrated by a .php.jpg filename.