The Single-user-chat plugin for WordPress is vulnerable to unauthorized modification of data that can lead to a denial of service due to insufficient validation on the 'single_user_chat_update_login' function in all versions up to, and including, 0.5. This makes it possible for authenticated attackers, with subscriber-level access and above, to update option values to 'login' on the WordPress site. This may be leveraged to update an option that would create an error on the site and deny service to legitimate users or be used to set some values to true such as registration.

The Freemius SDK, as used by hundreds of WordPress plugin and theme developers, was vulnerable to Cross-Site Request Forgery and Information disclosure due to missing capability checks and nonce protection on the _get_debug_log, _get_db_option, and the _set_db_option functions in versions up to, and including 2.4.2. Any WordPress plugin or theme running a version of Freemius less than 2.4.3 is vulnerable.