In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the CommBuffer and CommBufferSize parameters, allowing callers to corrupt either the firmware or the OS memory. The fixed versions for this issue in the PnpSmm, SmmResourceCheckDxe, and BeepStatusCode drivers are 05.08.23, 05.16.23, 05.26.23, 05.35.23, 05.43.23, and 05.51.23 (for Kernel 5.0 through 5.5).