CVE-2026-97876

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.

CVSS v3 6.4 MEDIUM

6.4^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 0.5 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/26beaa3b2720fefdc4d04c1ae209b776fe6848d6
https://www.openwall.com/lists/oss-security/2026/09/13/5

Configurations

No configuration.

History

02 Oct 2026, 11:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-02 11:17

Updated : 2026-10-02 18:44

NVD link : CVE-2026-97876

Mitre link : CVE-2026-97876

CVE.ORG link : CVE-2026-97876

JSON object : View

Products Affected

No product.

CWE

CWE-822

Untrusted Pointer Dereference

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