An issue was discovered in NvmExpressDxe in the kernel 5.0 through 5.5 in Insyde InsydeH2O. Because of an Untrusted Pointer Dereference that causes SMM memory corruption, an attacker may be able to write fixed or predictable data to SMRAM. Exploiting this issue could lead to escalating privileges to SMM.

A vulnerability exists in SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated table variable EFI_BOOT_SERVICES. This can be used by an attacker to overwrite address location of any of the functions (FreePool,LocateHandleBuffer,HandleProtocol) to the address location of arbitrary code controlled by the attacker. On system call to SWSMI handler, the arbitrary code can be triggered to execute.