---
id: CVE-2026-97876
title: >-
  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 …
summary: >-
  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 …
severity: medium
cvss: 6.4
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-822
vendor: GNU
product: grub2
affected:
  - grub2 >= 2.12 < 2.16
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T18:44:11.270'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97876'
references:
  - url: >-
      https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/26beaa3b2720fefdc4d04c1ae209b776fe6848d6
    label: security@ubuntu.com
  - url: 'https://www.openwall.com/lists/oss-security/2026/09/13/5'
    label: security@ubuntu.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97876.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-97876'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2545014'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-97876'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97876'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-02T17:44:52.729699Z'
ingestedAt: '2026-10-02T11:16:44.277Z'
epss: 0.00115
epssPercentile: 0.01508
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-02 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97876.json)