An issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. IHISI function 0x17 verifies that the output buffer lies within the command buffer but does not verify that output data does not go beyond the end of the command buffer. In particular, the GetFlashTable function is called directly on the Command Buffer before the DataSize is check, leading to possible circumstances where the data immediately following the command buffer could be destroyed before returning a buffer size error.

An issue was discovered in IhisiSmm in Insyde InsydeH2O with kernel 5.0 through 5.5. Specially formatted buffer contents used for software SMI could cause SMRAM corruption, leading to escalation of privilege.