CVE-2026-78175

The Tutor LMS – eLearning and online course solution plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 4.0.7 via the withdraw_method_field parameter of the tutor_save_withdraw_account AJAX handler. This is due to the handler lacking any capability or role check, relying solely on a nonce, while also passing attacker-supplied values through esc_sql(), which replaces every % character with a 66-byte HMAC placeholder token before the data is serialized and stored via update_user_meta(); when the meta is later retrieved, the placeholder is collapsed back to a single %, leaving serialized string length declarations 65 bytes greater than the actual content, and because array keys originate from entirely unescaped POST field names, unserialize() over-reads into attacker-controlled bytes, allowing injection of an arbitrary serialized object stream. This makes it possible for authenticated attackers, with subscriber-level access and above, to achieve remote code execution on the server by triggering the GuzzleHttp\Cookie\FileCookieJar POP chain, reachable via the spl_autoload_register loader in TUTOR\RestAPI which loads the plugin's own bundled PayPal Composer autoloader, writing attacker-controlled content to an attacker-specified filename. This has an unauthenticated pathway when user registration is enabled, which is common for students and teachers to register, and it requires the monetization feature to be enabled.