The Crypto plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 2.15. This is due a to limited arbitrary method call to 'crypto_connect_ajax_process::log_in' function in the 'crypto_connect_ajax_process' function. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the username.