MediaTek chipset: privilege escalation

In sec boot, there is a possible escalation of privilege due to a heap buffer overflow. This could lead to local escalation of privilege, if an attacker has physical access to the device, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: AUTO00845351 (Note: For MT2737) / ALPS11072643 (Note: For MT6880, MT6890, MT6990); Issue ID: MSV-6929.