An stack buffer overflow vulnerability leads to arbitrary code execution issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. If the attacker modifies specific UEFI variables, it can cause a stack overflow, leading to arbitrary code execution. The specific variables are normally locked (read-only) at the OS level and therefore an attack would require direct SPI modification. If an attacker can change the values of at least two variables out of three (SecureBootEnforce, SecureBoot, RestoreBootSettings), it is possible to execute arbitrary code.