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, callback function SmmCreateVariableLockList () calls CreateVariableLockListInSmm (). In CreateVariableLockListInSmm (), it uses StrSize () to get variable name size and it could lead to a buffer over-read.