CVE-2019-16241

On TCL Alcatel Cingular Flip 2 B9HUAH1 devices, PIN authentication can be bypassed by creating a special file within the /data/local/tmp/ directory. The System application that implements the lock screen checks for the existence of a specific file and disables PIN authentication if it exists. This file would typically be created via Android Debug Bridge (adb) over USB.

Source: CVE-2019-16241