Invoice Generator <= 1.0.0 - Unauthenticated Privilege Escalation via Account Takeover via 'user_id' Parameter

Summary

The Invoice Generator plugin for WordPress is vulnerable to privilege escalation due to a missing capability check on the pravel_invoice_edit_account() AJAX action in versions up to, and including, 1.0.0. The handler is exposed via wp_ajax_nopriv_pravel_invoice_edit_account, accepts an attacker-controlled user_id and user_email from POST data, and calls wp_update_user() without verifying authentication, ownership, or a nonce. This makes it possible for unauthenticated attackers to change the email address of any user, including administrators, and then trigger WordPress's password reset flow to gain access to the targeted account.