The Newtec Celox UHD devices (models CELOXA504 and CELOXA820) running firmware celox-21.6.13 have an authentication bypass vulnerability. An attacker can exploit this by modifying intercepted responses from the /celoxservice endpoint during the loginWithUserName process, allowing unauthorized Superuser or Operator access without valid credentials. This vulnerability has a critical severity with a CVSS score of 9.8.