---
id: CVE-2025-0677
title: A flaw was found in grub2
summary: >-
  A flaw was found in grub2. When performing a symlink lookup, the grub's UFS
  module checks the inode's data size to allocate the internal buffer to read
  the file content, however, it fails to check if the symlink data size has
  overflown. …
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
published: '2025-02-19'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-0677'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2025:16154'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2025:6990'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2025-0677'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2346116'
    label: secalert@redhat.com
  - url: 'https://lists.gnu.org/archive/html/grub-devel/2025-02/msg00024.html'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00328
epssPercentile: 0.26176
ingestedAt: '2026-06-29T13:24:34.163Z'
---

## Overview

A flaw was found in grub2. When performing a symlink lookup, the grub's UFS module checks the inode's data size to allocate the internal buffer to read the file content, however, it fails to check if the symlink data size has overflown. When this occurs, grub_malloc() may be called with a smaller value than needed. When further reading the data from the disk into the buffer, the grub_ufs_lookup_symlink() function will write past the end of the allocated size. An attack can leverage this by crafting a malicious filesystem, and as a result, it will corrupt data stored in the heap, allowing for arbitrary code execution used to by-pass secure boot mechanisms.

## Remediation

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