Arbitrary Code execution via exposed JTAG port in Kioxia CM6, PM6, PM7

There exists an unauthenticated accessible JTAG port on the Kioxia PM6, PM7 and CM6 devices - On the Kioxia CM6, PM6 and PM7 disk drives it was discovered that the 2 main CPU cores of the SoC can be accessed via an open JTAG debug port that is exposed on the drive’s circuit board. Due to the wide cutout of the enclosures, the JTAG port can be accessed without having to open the disk enclosure. Utilizing the JTAG debug port, an attacker with (temporary) physical access can get full access to the firmware and memory on the 2 main CPU cores within the drive including the execution of arbitrary code, the modification of firmware execution flow and data or bypassing the firmware signature verification during boot-up.