RHSA-2022:5096: Important: grub2, mokutil, shim, and shim-unsigned-x64 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 grubnetrecvip4packets (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: shimlock verifier allows non-kernel files to be loaded (CVE-2022-28735) grub2: use-after-free in grubcmdchainloader() (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.