---
id: CVE-2025-0685
title: A flaw was found in grub2
summary: >-
  A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs
  filesystem module uses user-controlled parameters from the filesystem geometry
  to determine the internal buffer size, however, it improperly checks for
  intege…
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-2025-0685'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2025-0685'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2346120'
    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: 0.20463
ingestedAt: '2026-06-26T16:43:13.413Z'
---

## Overview

A flaw was found in grub2. When reading data from a jfs filesystem, grub's jfs filesystem module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciouly 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_jfs_lookup_symlink() function will write past the internal buffer length during grub_jfs_read_file(). This issue can be leveraged to corrupt grub's internal critical data and may 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.