---
id: CVE-2025-0686
title: A flaw was found in grub2
summary: >-
  A flaw was found in grub2. When performing a symlink lookup from a romfs
  filesystem, grub's romfs filesystem module uses user-controlled parameters
  from the filesystem geometry to determine the internal buffer size, however,
  it improperl…
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-787
vendor: gnu
product: grub2
affected:
  - grub2 <= 2.12
published: '2025-03-03'
updated: '2026-06-26'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-0686'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2025-0686'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2346121'
    label: secalert@redhat.com
  - url: 'https://lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.html'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00278
epssPercentile: 0.20459
ingestedAt: '2026-06-26T16:43:13.414Z'
---

## Overview

A flaw was found in grub2. When performing a symlink lookup from a romfs filesystem, grub's romfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grub_malloc() operation with a smaller size than expected. As a result, the grub_romfs_read_symlink() may cause out-of-bounds writes when the calling grub_disk_read() function. This issue may be leveraged to corrupt grub's internal critical data and can result in arbitrary code execution by-passing secure boot protections.

## Affected

- `grub2 <= 2.12`

## Remediation

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