Máté Kukri

**Name of the Vulnerable Software and Affected Versions** grub2 versions prior to 2.06 **Description** A flaw was found in grub2 where it incorrectly enables the usage of the ACPI command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable content directly into memory. The table is further loaded and executed by the kernel, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code. The highest threat from this vulnerability is to data confidentiality and integrity, as well as system availability. **Recommendations** For versions prior to 2.06, update to version 2.06 or later to resolve the issue. As a temporary workaround, consider disabling the usage of ACPI commands when Secure Boot is enabled until a patch is available. Restrict access to the SSDT table to minimize the risk of exploitation. Avoid using the `ACPI` command in the grub2 configuration file until the issue is resolved.