The IBM Power 9 OP910, OP920, and FW910 boot firmware's bootloader is responsible for loading and validating the initial boot firmware image that drives the rest of the system's hardware initialization. The bootloader firmware contains a buffer overflow vulnerability such that, if an attacker were able to replace the initial boot firmware image with a very carefully crafted and sufficiently large, malicious replacement, it could cause the bootloader, during the load of that image, to overwrite its own instruction memory and circumvent secure boot protections, install trojans, etc. IBM X-Force ID: 154345.