Linux Kernel KVM SMM Vulnerability Leading to Out-of-Bound Memory Access

A vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) component has been identified, specifically related to the handling of System Management Mode (SMM) images. On 64-bit hosts, if the guest does not support long mode, KVM accesses 16 general-purpose registers (GPRs) in a 32-bit SMM image, leading to out-of-bounds memory access. Conversely, on 32-bit hosts, the relevant state-saving functions are not compiled, preventing such overflow issues.

Impact

Exploitation of this vulnerability causes out-of-bounds memory access, which can lead to undefined behavior, including potential memory corruption or information disclosure.