An issue was discovered in SdHostDriver in the kernel 5.0 through 5.5 in Insyde InsydeH2O. There is an SMM callout that allows an attacker to access the System Management Mode and execute arbitrary code. This occurs because of a Numeric Range Comparison Without a Minimum Check.

An unsafe pointer vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler. An attacker can use this unsafe pointer "ptr" to read or write or manipulate data in the SMRAM. Exploitation of this vulnerability can lead to escalation of privileges reserved only for SMM using the SwSMI handler.