The USB firmware update script of homee Brain Cube v2 (2.28.2 and 2.28.4) devices allows an attacker with physical access to install compromised firmware. This occurs because of insufficient validation of the firmware image file and can lead to code execution on the device.
https://www.syss.de/pentest-blog/
https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-026.txt