Overview System Management Mode (SMM) memory corruption vulnerabilities have been identified in UEFI modules present in AMI Aptio UEFI firmware. An attacker could exploit this vulnerability to elevate privileges and execute arbitrary code in the highly privileged SMM environment. Users should apply UEFI firmware updates provided by their supply-chain-supported vendors to address these issues. Description The Unified Extensible Firmware Interface (UEFI) specification defines an interface between an operating system (OS) and platform firmware. The UEFI specification defines mechanisms that allow firmware code to execute in System Management Mode (SMM), a highly privileged CPU mode intended for low-level system operations and direct hardware access. SMM operations are executed within a CPU protected memory region called System Management RAM (SMRAM). This environment is often referred to as "ring -2" because it operates at a deeper privilege level than the OS kernel (ring 0) and hypervisor (ring -1). A vulnerability has been identified in certain firmware modules of AMI APTIOV related to improper pointer validation. Specifically, the code fails to adequately validate pointer values to prevent overlap with SMRAM. This allows memory references to be redirected into SMRAM, potentially enabling unauthorized code execution within SMM. An attacker exploiting this flaw could corrupt memory and overwrite sensitive SMRAM data, including firmware components that may later be written to…Read More