Stack overflow vulnerability in SMI handler on SmmSmbiosElog.

An attacker can exploit this vulnerability to elevate privileges from ring 0 to ring -2, execute arbitrary code in System Management Mode - an environment more privileged than operating system (OS) and completely isolated from it. Running arbitrary code in SMM additionally bypasses SMM-based SPI flash protections against modifications, which can help an attacker to install a firmware backdoor/implant into BIOS. Such a malicious firmware code in BIOS could persist across operating system re-installs. Additionally, this vulnerability potentially could be used by malicious actors to bypass security mechanisms provided by UEFI firmware (for example, Secure Boot and some types of memory isolation for hypervisors). This issue affects: Module name: SmmSmbiosElog SHA256: 3a8acb4f9bddccb19ec3b22b22ad97963711550f76b27b606461cd5073a93b59 Module GUID: 8e61fd6b-7a8b-404f-b83f-aa90a47cabdf This issue affects: AMI Aptio 5.x. This issue affects: AMI Aptio 5.x.