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, VariableServicesSetVariable () can be called by gRT_>SetVariable () or the SmmSetSensitiveVariable () or SmmInternalSetVariable () from SMM. In VariableServicesSetVariable (), it uses StrSize () to get variable name size, uses StrLen () to get variable name length and uses StrCmp () to compare strings. These actions 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.