Ampere AmpereOne AC03 devices before 3.5.9.3, AmpereOne AC04 devices before 4.4.5.2, and AmpereOne M devices before 5.4.5.1 allow an incorrectly formed SMC call to UEFI-MM MMCommunicate service that could result in an out-of-bounds write within the UEFI-MM Secure Partition context.
References