A vulnerability has been identified in some Lenovo products that use UEFI (BIOS) code developed by American Megatrends, Inc. (AMI). With this vulnerability, conditions exist where an attacker with administrative privileges or physical access to a system may be able to run specially crafted code that can allow them to bypass system protections such as Device Guard and Hyper-V.

In Lenovo systems, SMM BIOS Write Protection is used to prevent writes to SPI Flash. While this provides sufficient protection, an additional layer of protection is provided by SPI Protected Range Registers (PRx). Lenovo was notified that after resuming from S3 sleep mode in various versions of BIOS for Lenovo systems, the PRx is not set. This does not impact the SMM BIOS Write Protection, which keeps systems protected.