Summary
Máté Kukri discovered that the acpi command in GRUB 2 allowed privileged
users to load crafted ACPI tables when secure boot is enabled. An attacker
could use this to bypass UEFI Secure Boot restrictions. (CVE-2020-14372)
Chris Coulson discovered that the rmmod command in GRUB 2 contained a use-
after-free vulnerability. A local attacker could use this to execute
arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-25632)
Chris Coulson discovered that a buffer overflow existed in the command line
parser in GRUB 2. A local attacker could use this to execute arbitrary code
and bypass UEFI Secure Boot restrictions. (CVE-2020-27749)
It was discovered that the cutmem command in GRUB 2 did not honor secure
boot locking. A local attacker could use this to execute arbitrary code and
bypass UEFI Secure Boot restrictions. (CVE-2020-27779)
It was discovered that the option parser in GRUB 2 contained a heap
overflow vulnerability. A local attacker could use this to execute
arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2021-20225)
It was discovered that the menu rendering implementation in GRUB 2 did not
properly calculate the amount of memory needed in some situations, leading
to out-of-bounds writes. A local attacker could use this to execute
arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2021-20233)
Fixed packages 4
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · 18.04 LTS 18.04:LTS | grub2-signed | 1.167~18.04.5 |
| Ubuntu · 18.04 LTS 18.04:LTS | grub2-unsigned | 2.04-1ubuntu44.1.2 |
| Ubuntu · 20.04 LTS 20.04:LTS | grub2-signed | 1.167.2 |
| Ubuntu · 20.04 LTS 20.04:LTS | grub2-unsigned | 2.04-1ubuntu44.2 |
Vulnerabilities 6
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Unscored —CVE-2020-14372 Public exploit
A flaw was found in grub2 in versions prior to 2.06, where it incorrectly enables the usage of the ACPI command when Se…
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Unscored —CVE-2020-25632 Public exploit
A flaw was found in grub2 in versions prior to 2.06. The rmmod implementation allows the unloading of a module used as …
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Unscored —
A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line i…
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Unscored —
A flaw was found in grub2 in versions prior to 2.06. The cutmem command does not honor secure boot locking allowing an …
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Unscored —
A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a he…
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Unscored —CVE-2021-20233 Public exploit
A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length cal…