An issue was discovered in Insyde InsydeH2O kernel 5.2 before version 05.29.50, kernel 5.3 before version 05.38.50, kernel 5.4 before version 05.46.50, kernel 5.5 before version 05.54.50, kernel 5.6 before version 05.61.50, and kernel 5.7 before version 05.70.50. In VariableRuntimeDxe driver, SmmUpdateVariablePropertySmi () is a SMM callback function and it uses StrCmp () to compare variable names. This action may cause a buffer over-read.
The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.