CVE-2026-100392 InvoicePlane: Primary Administrator Privilege Downgrade via `Users::form()` (Missing Object-Level Authorization)

InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. In version 1.7.2, Users::form performs no object-level authorization check on userid = 1. A Secondary Administrator usertype = 1, userid != 1 can rewrite the Primary Administrator's usertype to 2...