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 Boot Error Record Table driver that could result in (1) an out-of-bounds read which leaks Secure-EL0 information to a process running in Non-Secure state or (2) an out-of-bounds write which corrupts Secure or Non-Secure memory, limited to memory mapped to UEFI-MM Secure Partition by the Secure Partition Manager.