(RHSA-2022:5098) Important: grub2, mokutil, and shim security update

The grub2 packages provide version 2 of the Grand Unified Boot Loader (GRUB), a highly configurable and customizable boot loader with modular architecture. The packages support a variety of kernel formats, file systems, computer architectures, and hardware devices.

The shim package contains a first-stage UEFI boot loader that handles chaining to a trusted full boot loader under secure boot environments.

Security Fix(es):

• grub2: Integer underflow in grub_net_recv_ip4_packets (CVE-2022-28733)

• grub2: Crafted PNG grayscale images may lead to out-of-bounds write in heap (CVE-2021-3695)

• grub2: Crafted PNG image may lead to out-of-bound write during huffman table handling (CVE-2021-3696)

• grub2: Crafted JPEG image can lead to buffer underflow write in the heap (CVE-2021-3697)

• grub2: Out-of-bound write when handling split HTTP headers (CVE-2022-28734)

• grub2: shim_lock verifier allows non-kernel files to be loaded (CVE-2022-28735)

• grub2: use-after-free in grub_cmd_chainloader() (CVE-2022-28736)

• shim: Buffer overflow when loading crafted EFI images (CVE-2022-28737)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.