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Medium ALSA-2021:1734 7 CVEs

Moderate: shim security update

Published May 18, 2021 · Updated Oct 29, 2026

Ecosystem: AlmaLinux

Summary

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: acpi command allows privileged user to load crafted ACPI tables when Secure Boot is enabled (CVE-2020-14372)

* grub2: Use-after-free in rmmod command (CVE-2020-25632)

* grub2: Out-of-bounds write in grub_usb_device_initialize() (CVE-2020-25647)

* grub2: Stack buffer overflow in grub_parser_split_cmdline() (CVE-2020-27749)

* grub2: cutmem command allows privileged user to remove memory regions when Secure Boot is enabled (CVE-2020-27779)

* grub2: Heap out-of-bounds write in short form option parser (CVE-2021-20225)

* grub2: Heap out-of-bounds write due to miscalculation of space required for quoting (CVE-2021-20233)

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.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

Fixed packages 5

ReleasePackageFixed in
AlmaLinux · 8 shim-aa64 15.4-2.el8_1.alma
AlmaLinux · 8 shim-ia32 15.4-2.el8_1.alma
AlmaLinux · 8 shim-unsigned-aarch64 15-7.el8_1.alma
AlmaLinux · 8 shim-unsigned-x64 15.4-4.el8_1.alma
AlmaLinux · 8 shim-x64 15.4-2.el8_1.alma

Vulnerabilities 7

References

  • report
    https://vulners.com/cve/CVE-2020-14372
  • report
    https://vulners.com/cve/CVE-2020-25632
  • report
    https://vulners.com/cve/CVE-2020-25647
  • report
    https://vulners.com/cve/CVE-2020-27749
  • report
    https://vulners.com/cve/CVE-2020-27779
  • report
    https://vulners.com/cve/CVE-2021-20225
  • report
    https://vulners.com/cve/CVE-2021-20233