An issue was discovered on TK-Star Q90 Junior GPS horloge 3.1042.9.8656 devices. Any SIM card used with the device cannot have a PIN configured. If a PIN is configured, the device simply produces a "Remove PIN and restart!" message, and cannot be used. This makes it easier for an attacker to use the SIM card by stealing the device.

An issue was discovered on TK-Star Q90 Junior GPS horloge 3.1042.9.8656 devices. When using the device at initial setup, a default password is used (123456) for administrative purposes. There is no prompt to change this password. Note that this password can be used in combination with CVE-2019-20470.

An issue was discovered on TK-Star Q90 Junior GPS horloge 3.1042.9.8656 devices. It performs actions based on certain SMS commands. This can be used to set up a voice communication channel from the watch to any telephone number, initiated by sending a specific SMS and using the default password, e.g., pw,<password>,call,<mobile_number> triggers an outbound call from the watch. The password is sometimes available because of CVE-2019-20471.

An issue was discovered in SeTracker2 for TK-Star Q90 Junior GPS horloge 3.1042.9.8656 devices. It has unnecessary permissions such as READ_EXTERNAL_STORAGE, WRITE_EXTERNAL_STORAGE, and READ_CONTACTS.