Subaccounts for WooCommerce <= 1.6.6 - Authenticated (Subscriber+) Privilege Escalation via Account Takeover

The Subaccounts for WooCommerce plugin for WordPress is vulnerable to privilege escalation via account takeover in all versions up to, and including, 1.6.6. This is due to the plugin not properly validating a user's identity prior to updating their details like email through the sfwc_frontend_edit_subaccount_form_handler() function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to change arbitrary user's email addresses, including administrators, and leverage that to reset the user's password and gain access to their account.