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Fencer Vulns
medium 4.8

CVE-2025-61661 json

Grub2: grub2: out-of-bounds write via malicious usb device

published 2025-11-18 11 mo ago modified 2026-11-05 3 d ago also EUVD-2025-198081

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

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 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.

Patch / fix

  • grub2 Debian 14 2.14-1

debian advisories DEBIAN-CVE-2025-61661

  • grub2 SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 2.12-160000.3.1
  • grub2 SLE Module for Server Applications 15 SP7, SLE Module for Basesystem 15 SP7 2.12-150700.19.19.1
  • grub2 SLE Micro 5.4, SLE Micro 5.3 2.06-150400.11.66.1
  • grub2 SLE Module for Server Applications 15 SP6, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 2.12-150600.8.44.2
  • grub2 Linux Micro 6.1 2.12-slfo.1.1_3.1
  • grub2 SLE Micro 5.5 2.06-150500.29.59.1
  • grub2 SLE Micro 5.2 2.04-150300.22.61.1
  • grub2 SLES LTSS Extended Security 12 SP5 2.02-193.1

suse advisories SUSE-SU-2025:21212-1SUSE-SU-2025:21223-1SUSE-SU-2025:4305-1SUSE-SU-2025:4224-1SUSE-SU-2025:4197-1SUSE-SU-2025:4196-1

  • grub2 openSUSE Leap 16.0 2.12-160000.3.1
  • grub2 openSUSE Tumbleweed 2.12-67.1

opensuse advisories openSUSE-SU-2025:20163-1openSUSE-SU-2025:15749-1

  • grub2 CBL-Mariner 2.0 2.06-16
  • grub2 Azure Linux 3.0 2.06-26

azure linux advisories AZL-70526AZL-70580

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-61661 updated cvss 4.8

grub2: grub2: Out-of-bounds write via malicious USB device

  • Red Hat Enterprise Linux 7 grub2, grub2-pc, grub2-efi, grub2-ppc64, grub2-tools, grub2-common, +15 more Red Hat Enterprise Linux 8 grub2, grub2-pc, grub2-tools, grub2-common, grub2-efi-x64, grub2-ppc64le, +13 more Red Hat Enterprise Linux 9 grub2, grub2-pc, grub2-tools, grub2-common, grub2-efi-x64, grub2-ppc64le, +10 more Red Hat Enterprise Linux 10 grub2 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “As a mitigation Red Hat doesn't recommend to connect untrusted or unknown USB devices to the machine.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.8 CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

Affected products

  • GNU grub2
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat OpenShift Container Platform 4

Classification

Weakness
  • CWE-131 Incorrect Calculation of Buffer Size

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.