Overview System Management Mode (SMM) callout vulnerabilities have been identified in UEFI modules present in Gigabyte firmware. An attacker could exploit one or more of these vulnerabilities to elevate privileges and execute arbitrary code in the SMM environment of a UEFI-supported processor. While AMI (the original firmware supplier) has indicated that these vulnerabilities were previously addressed, they have resurfaced in Gigabyte firmware and are now being publicly disclosed. Description The Unified Extensible Firmware Interface (UEFI) specification defines an interface between an operating system (OS) and platform firmware. UEFI can interact directly with hardware using System Management Mode (SMM), a highly privileged CPU mode designed for handling low-level system operations. SMM operations are executed within a protected memory region called System Management RAM (SMRAM) and are only accessible through System Management Interrupt (SMI) handlers. SMI handlers act as a gateway to SMM and process data passed via specific communication buffers. Improper validation of these buffers or untrusted pointers from CPU save state registers can lead to serious security risks, including SMRAM corruption and unauthorized SMM execution. An attacker could abuse these SMI handlers to execute arbitrary code within the early boot phases, recovery modes, or before the OS fully loads. The following vulnerabilities were identified in Gigabyte firmware implementations: CVE-2025-7029 :…Read More