DMA transactions which are targeted at input buffers used for the SdMmcDevice software SMI handler could cause SMRAM corruption through a TOCTOU attack. DMA transactions which are targeted at input buffers used for the software SMI handler used by the SdMmcDevice driver could cause SMRAM corruption through a TOCTOU attack. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group. This was fixed in kernel 5.2: 05.27.25, kernel 5.3: 05.36.25, kernel 5.4: 05.44.25, kernel 5.5: 05.52.25 https://www.insyde.com/security-pledge/SA-2022054