An issue was discovered in AtaLegacySmm in the kernel 5.0 before 05.08.46, 5.1 before 05.16.46, 5.2 before 05.26.46, 5.3 before 05.35.46, 5.4 before 05.43.46, and 5.5 before 05.51.45 in Insyde InsydeH2O. Code execution can occur because the SMI handler lacks a CommBuffer check.