title: GRUB2 contains a race condition leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing.
description: GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions.
problem types: CWE-362 Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization)
affected:
{
product: grub2 in Ubuntu
vendor: Ubuntu
versions:
lessThan: 2.04-1ubuntu26.1, status: affected, version: 20.04 LTS, versionType: custom
lessThan: 2.02-2ubuntu8.16, status: affected, version: 18.04 LTS, versionType: custom
lessThan: 2.02~beta2-36ubuntu3.26, status: affected, version: 16.04 LTS, versionType: custom
lessThan: 2.02~beta2-9ubuntu1.20, status: affected, version: 14.04 ESM, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: HIGH
attackVector: LOCAL
availabilityImpact: HIGH
baseScore: 6.4
baseSeverity: MEDIUM
confidentialityImpact: HIGH
integrityImpact: HIGH
privilegesRequired: HIGH
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
version: 3.1
]