On eQ-3 HomeMatic CCU2 devices before 2.41.8 and CCU3 devices before 3.43.16, automatic login configuration (aka setAutoLogin) can be achieved by continuing to use a session ID after a logout, aka HMCCU-154.
eq-3
CVE-2019-10119
eQ-3 HomeMatic CCU2 devices before 2.41.8 and CCU3 devices before 3.43.16 use session IDs for authentication but lack authorization checks. An attacker can obtain a session ID via an invalid login attempt to the RemoteApi account, aka HMCCU-154. This leads to automatic login as admin.
CVE-2021-33032
A Remote Code Execution (RCE) vulnerability in the WebUI component of the eQ-3 HomeMatic CCU2 firmware up to and including version 2.57.5 and CCU3 firmware up to and including version 3.57.5 allows remote unauthenticated attackers to execute system commands as root via a simple HTTP request.