---
id: CVE-2025-61661
title: >-
  A vulnerability has been identified in the GRUB (Grand Unified Bootloader)
  component
summary: >-
  A vulnerability has been identified in the GRUB (Grand Unified Bootloader)
  component. This flaw occurs because the bootloader mishandles string
  conversion when reading information from a USB device, allowing an attacker to
  exploit incons…
severity: medium
cvss: 4.8
cvssVector: 'CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H'
cwe:
  - CWE-131
published: '2025-11-18'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-61661'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2025-61661'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2413827'
    label: secalert@redhat.com
  - url: 'http://www.openwall.com/lists/oss-security/2025/11/18/8'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00194
epssPercentile: 0.08028
ingestedAt: '2026-06-29T13:24:34.606Z'
---

## Overview

A vulnerability has been identified in the GRUB (Grand Unified Bootloader) component. This flaw occurs because the bootloader mishandles string conversion when reading information from a USB device, allowing an attacker to exploit inconsistent length values. A local attacker can connect a maliciously configured USB device during the boot sequence to trigger this issue. A successful exploitation may lead GRUB to crash, leading to a Denial of Service. Data corruption may be also possible, although given the complexity of the exploit the impact is most likely limited.

## Remediation

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