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Fencer Vulns
medium 5.3

CVE-2023-4693 json

Grub2: out-of-bounds read at fs/ntfs.c

published 2023-10-25 3 y ago modified 2026-11-07 2 d ago also EUVD-2023-54544

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

An out-of-bounds read flaw was found on grub2's NTFS filesystem driver. This issue may allow a physically present attacker to present a specially crafted NTFS file system image to read arbitrary memory locations. A successful attack allows sensitive data cached in memory or EFI variable values to be leaked, presenting a high Confidentiality risk.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 8 1:2.02-156.el8
  • Red Hat Red Hat Enterprise Linux 9 1:2.06-77.el9
  • grub2 Debian 12 2.06-13+deb12u1
  • grub2 Debian 14, Debian 13 2.12~rc1-11

debian advisories DEBIAN-CVE-2023-4693

  • grub2-signed Ubuntu 20.04 LTS 1.187.6~20.04.1
  • grub2-signed Ubuntu 22.04 LTS 1.187.6
  • grub2-signed Ubuntu 24.04 LTS 1.199
  • grub2-unsigned Ubuntu 22.04 LTS, Ubuntu 20.04 LTS 2.06-2ubuntu14.4

ubuntu advisories UBUNTU-CVE-2023-4693

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • grub2 RHEL 8 1:2.02-156.el8
  • grub2-pc RHEL 8 1:2.02-156.el8
  • grub2-tools RHEL 8 1:2.02-156.el8
  • grub2-common RHEL 8 1:2.02-156.el8
  • grub2-efi-x64 RHEL 8 1:2.02-156.el8
  • grub2-ppc64le RHEL 8 1:2.02-156.el8
  • grub2-efi-aa64 RHEL 8 1:2.02-156.el8
  • grub2-efi-ia32 RHEL 8 1:2.02-156.el8

red hat advisories RHSA-2024:3184RHSA-2024:2456

  • grub2 SLE Micro 5.1 2.04-150300.3.11.1
  • grub2 SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 2.06-150500.29.8.1
  • grub2 SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +2 more 2.06-150400.11.38.1
  • grub2 SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +6 more 2.04-150300.22.43.1
  • grub2 SLES for SAP 12 SP5, SLES 12 SP5 2.02-169.1

suse advisories SUSE-SU-2025:01961-1SUSE-SU-2023:4141-1SUSE-SU-2023:4140-1SUSE-SU-2023:4130-1SUSE-SU-2023:4085-1

  • grub2 openSUSE Tumbleweed 2.12~rc1-5.1

opensuse advisories openSUSE-SU-2024:13328-1

  • grub2-pc AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-tools AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-common AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-efi-x64 AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-ppc64le AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-efi-aa64 AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-efi-ia32 AlmaLinux 8 1:2.02-156.el8.alma.1
  • grub2-tools-efi AlmaLinux 8 1:2.02-156.el8.alma.1

almalinux advisories ALSA-2024:3184ALSA-2024:2456

  • grub2 Rocky Linux 8 1:2.02-156.el8.rocky.0.1

rocky linux advisories RLSA-2024:3184

  • grub2 CBL-Mariner 2.0 2.06-13
  • grub2 Azure Linux 3.0 2.06-18

azure linux advisories AZL-31685AZL-34794

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-2023-4693 updated cvss 5.3

grub2: out-of-bounds read at fs/ntfs.c

  • Red Hat Enterprise Linux 7 grub2, grub2-pc, grub2-efi, grub2-ppc64, grub2-tools, grub2-common, +15 more
    affected: no fix available
  • Red Hat Enterprise Linux BaseOS (v. 8) grub2 2.02-156.el8, grub2-pc 2.02-156.el8, grub2-tools 2.02-156.el8, grub2-common 2.02-156.el8, grub2-efi-x64 2.02-156.el8, grub2-ppc64le 2.02-156.el8, +13 more
    fixed: vendor fix RHSA-2024:3184
  • Red Hat Enterprise Linux BaseOS (v. 9) grub2 2.06-77.el9, grub2-pc 2.06-77.el9, grub2-tools 2.06-77.el9, grub2-common 2.06-77.el9, grub2-efi-x64 2.06-77.el9, grub2-ppc64le 2.06-77.el9, +10 more
    fixed: vendor fix RHSA-2024:2456

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
6 d ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • dfir.ru https://dfir.ru/2023/10/03/cve-2023-4692-cve-2023-4693-vulnerabilities-in-the-grub-boot-manager/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
NVD 3.1 4.6 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness

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.