DMA attacks on the parameter buffer used by the VariableRuntimeDxe software SMI handler could lead to a TOCTOU attack. DMA attacks on the parameter buffer used by the software SMI handler used by the driver VariableRuntimeDxe could lead to a TOCTOU attack on the SMI handler and lead to corruption of SMRAM. This issue was discovered by Insyde engineering during a security review. This issue is fixed in Kernel 5.4: 05.44.23 and Kernel 5.5: 05.52.23. CWE-367 CWE-367 Report at: https://www.insyde.com/security-pledge/SA-2022056