The AppPresser plugin for WordPress is vulnerable to improper missing encryption exception handling on the 'decrypt_value' and on the 'doCookieAuth' functions in all versions up to, and including, 4.3.2. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they previously used the login via the plugin API. This can only be exploited if the 'openssl' php extension is not loaded on the server.