yangtian_ytm6900e-00_firmware

Lenovo was notified of a potential denial of service vulnerability, affecting various versions of BIOS for Lenovo Desktop, Desktop – All in One, and ThinkStation, that could cause PCRs to be cleared intermittently after resuming from sleep (S3) on systems with Intel TXT enabled.

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.

Realtek Audio Drivers for Windows, as used on the Lenovo ThinkPad X1 Carbon 20A7, 20A8, 20BS, and 20BT before 6.0.8882.1 and 20KH and 20KG before 6.0.8907.1 (and on many other Lenovo and non-Lenovo products), mishandles DLL preloading.