The grub2 packages provide version 2 of the Grand Unified Boot Loader , 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. The fwupdate packages provide a service that allows session software to update device firmware. Security Fix: * grub2: Crafted grub.cfg file can lead to arbitrary code execution during boot process * grub2: grub_malloc does not validate allocation size allowing for arithmetic overflow and subsequent heap-based buffer overflow * grub2: Integer overflow in grub_squash_read_symlink may lead to heap-based buffer overflow * grub2: Integer overflow read_section_as_string may lead to heap-based buffer overflow * grub2: Integer overflow in grub_ext2_read_link leads to heap-based buffer overflow * grub2: Fail kernel validation without shim protocol * grub2: Use-after-free redefining a function whilst the same function is already executing * grub2: Integer overflow in initrd size handling For more details about the security issue, including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page listed in the References section. Bug Fix: * grub2 doesn"t handle relative paths correctly for UEFI HTTP Boot * UEFI HTTP boot over IPv6 does not work Users of grub2 are advised to upgrade to these updated packages, which fix these bugs.