Red Hat Shim

Out-of-Bounds Read in MZ Binary Format of Windows Shim
CVE-2023-40551 5.1 - Medium - January 29, 2024

A flaw was found in the MZ binary format in Shim. An out-of-bounds read may occur, leading to a crash or possible exposure of sensitive data during the system's boot phase.

Out-of-bounds Read

Windows Shim ESL Variable Creation Format String Crash
CVE-2023-40546 6.2 - Medium - January 29, 2024

A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create the new variable, it tries to print an error message to the user; however, the number of parameters used by the logging function doesn't match the format string used by it, leading to a crash under certain circumstances.

NULL Pointer Dereference

Shim OOBR read leaks sensitive data during boot
CVE-2023-40550 5.5 - Medium - January 29, 2024

An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the system's boot phase.

Out-of-bounds Read

Windows Shim OOB Read via PE Binary Load
CVE-2023-40549 6.2 - Medium - January 29, 2024

An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the load of a PE binary. This flaw allows an attacker to load a crafted PE binary, triggering the issue and crashing Shim, resulting in a denial of service.

Out-of-bounds Read

Heap-Based Buffer Overflow in Windows Shim via PE User-Controlled Size
CVE-2023-40548 7.4 - High - January 29, 2024

A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes memory corruption and can lead to a crash or data integrity issues during the boot phase.

Memory Corruption

RCE in Shim Bootloader via OOB Write (CVE-2023-40547)
CVE-2023-40547 8.3 - High - January 25, 2024

A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise. This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the-Middle or compromise the boot server to be able to exploit this vulnerability successfully.

Memory Corruption

CVE-2022-28737: shim handle_image OOB write
CVE-2022-28737 7.8 - High - July 20, 2023

There's a possible overflow in handle_image() when shim tries to load and execute crafted EFI executables; The handle_image() function takes into account the SizeOfRawData field from each section to be loaded. An attacker can leverage this to perform out-of-bound writes into memory. Arbitrary code execution is not discarded in such scenario.

Memory Corruption

Unspecified vulnerability in Shim might
CVE-2014-3677 - October 22, 2014

Unspecified vulnerability in Shim might allow attackers to execute arbitrary code via a crafted MOK list, which triggers memory corruption.

Shim allows remote attackers to cause a denial of service (out-of-bounds read)
CVE-2014-3675 - October 22, 2014

Shim allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted DHCPv6 packet.

Heap-based buffer overflow in Shim
CVE-2014-3676 - October 22, 2014

Heap-based buffer overflow in Shim allows remote attackers to execute arbitrary code via a crafted IPv6 address, related to the "tftp:// DHCPv6 boot option."