GNU GRUB up to 2.15 Serial Command privileges management

Summaryinfo

A vulnerability described as very critical has been identified in GNU GRUB up to 2.15. This issue affects some unknown processing of the component Serial Command. Such manipulation leads to privileges management. This vulnerability is traded as CVE-2026-97876. An attack has to be approached locally. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in GNU GRUB up to 2.15. It has been rated as very critical. Affected by this issue is an unknown code block of the component Serial Command. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A local attacker with control over GRUB's configuration can bypass lockdown restrictions when booting with Secure Boot and load an unsigned GRUB module, while GRUB continues to report lockdown is enabled. The vulnerability is caused by insufficient validation of the MMIO base address passed to the GRUB serial command. GRUB does not validate that the base address corresponds to a UART device, rather than being an arbitrary memory address. This allows an attacker to trick GRUB into writing non-arbitrary data at an attacker-controlled address, including resetting the grub_file_verifiers list in a way that disables the subsequent verification of loaded modules.

The advisory is available at openwall.com. This vulnerability is handled as CVE-2026-97876 since 09/25/2026. The exploitation is known to be easy. Local access is required to approach this attack. Additional levels of successful authentication are needed for exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/02/2026). This vulnerability is assigned to T1068 by the MITRE ATT&CK project.

Upgrading to version 2.16 eliminates this vulnerability.

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Productinfo

Vendor

• GNU

Name

• GRUB

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15

License

• open-source

Website

• Vendor: https://www.gnu.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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