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Medium RLSA-2021:1734 7 CVEs

Moderate: shim security update

Published May 18, 2021 · Updated Feb 5, 2026

Ecosystem: Rocky Linux

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 Rocky Linux 8.4 Release Notes linked from the References section.

Fixed packages 1

ReleasePackageFixed in
Rocky Linux · 8 shim-unsigned-aarch64 0:15-7.el8.1.1

Vulnerabilities 7

References

  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1873150
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1879577
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1886936
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1899966
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1900698
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1924696
  • report
    https://bugzilla.redhat.com/show_bug.cgi?id=1926263