The Easy Digital Downloads plugin for WordPress is vulnerable to authentication bypass leading to...

The Easy Digital Downloads plugin for WordPress is vulnerable to authentication bypass leading to administrator account takeover in all versions up to, and including, 3.7.2. During a PayPal guest checkout, the email address entered in the guest-checkout field is trusted as proof of identity: edd_get_purchase_form_user() binds the new guest order to an existing WordPress user purely on an email-address match, rewriting the order's user_id to that user's ID. The PayPal capture sink PurchaseUser::maybe_log_in_after_capture() then looked the user up by the order email (get_user_by( 'email', $order->email )) and, when $order->user_id equalled that user's ID (which the email-binding step guarantees), issued an authenticated session with wp_set_auth_cookie(). An unauthenticated attacker who starts a guest checkout using an administrator's email address (where that administrator has no existing EDD customer record) and completes the PayPal purchase flow therefore receives an authenticated session as that administrator — a full account takeover. The same sink is reachable through the standard PayPal checkout and the REST UnbrandedCard and Fastlane flows.