The Really Simple Security (Free, Pro, and Pro Multisite) plugins for WordPress are vulnerable to authentication bypass in versions 9.0.0 to 9.1.1.1. This is due to improper user check error handling in the two-factor REST API actions with the 'check_login_and_get_user' function. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, when the "Two-Factor Authentication" setting is enabled (disabled by default).

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.