Shim: interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems

CVE-2023-40548

Summary

A buffer overflow vulnerability exists in the Shim component of the 32-bit system environment. It arises from an addition operation that involves user-controlled values parsed from Portable Executable (PE) binaries used by Shim. This maliciously manipulated value is leveraged during memory allocation processes, which can lead to heap-based buffer overflow conditions. The potential consequences of this flaw include memory corruption that may result in system crashes or impact data integrity during crucial boot sequences. Rigorous attention to the associated advisories is recommended for users utilizing affected Shim versions.

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