With physical access to the device and enough time an attacker is able to solder test leads to the debug footprint (or use the 6-Pin tag-connect cable). Thus, the attacker gains access to the bootloader, where the kernel command line can be changed. An attacker is able to gain a root shell through this vulnerability.
Weakness
System configuration protection may be bypassed during debug mode.
Extended Description
Device configuration controls are commonly programmed after a device power reset by a trusted firmware or software module (e.g., BIOS/bootloader) and then locked from any further modification. This is commonly implemented using a trusted lock bit, which when set, disables writes to a protected set of registers or address regions. The lock protection is intended to prevent modification of certain system configuration (e.g., memory/memory protection unit configuration). If debug features supported by hardware or internal modes/system states are supported in the hardware design, modification of the lock protection may be allowed allowing access and modification of configuration information.