(RHSA-2024:1959) Important: shim security update

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):

• shim: RCE in http boot support may lead to Secure Boot bypass (CVE-2023-40547)

• shim: Interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems (CVE-2023-40548)

• shim: Out-of-bounds read printing error messages (CVE-2023-40546)

• shim: Out-of-bounds read in verify_buffer_authenticode() malformed PE file (CVE-2023-40549)

• shim: Out-of-bound read in verify_buffer_sbat() (CVE-2023-40550)

• shim: out of bounds read when parsing MZ binaries (CVE-2023-40551)

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.

IMPORTANT: The new shim revokes ALL VERSIONS of GRUB2 before grub2-2.02-0.87.el7_9.14. Therefore GRUB2 MUST be updated to the latest
version: grub2-2.02-0.87.el7_9.14 BEFORE or SIMULTANEOUSLY with this shim in order for Secure Boot to continue to work. Failure to update GRUB2 will result in an UNBOOTABLE system.