An issue was discovered in the IhisiServiceSmm module in Insyde InsydeH2O with kernel 5.2 before 05.28.42, 5.3 before 05.37.42, 5.4 before 05.45.39, 5.5 before 05.53.39, and 5.6 before 05.60.39 that could allow an attacker to modify UEFI variables.