An issue was discovered in PnpSmm in Insyde InsydeH2O with kernel 5.0 through 5.6. There is a possible out-of-bounds access in the SMM comm…

An issue was discovered in PnpSmm in Insyde InsydeH2O with kernel 5.0 through 5.6. There is a possible out-of-bounds access in the SMM communication buffer, leading to tampering. The PNP-related SMI sub-functions do not verify data size before getting it from the communication buffer, which could lead to possible circumstances where the data immediately following the command buffer could be destroyed with a fixed value. This is fixed in kernel 5.2 v05.28.45, kernel 5.3 v05.37.45, kernel 5.4 v05.45.45, kernel 5.5 v05.53.45, and kernel 5.6 v05.60.45.