CVE-2023-4693: An out-of-bounds read flaw was found on grub2's NTFS filesystem driver

Q: How do I fix CVE-2023-4693?

grub2: upgrade to 2.12; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2023-4693 being exploited?

CVE-2023-4693 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-4693 affect?

CVE-2023-4693 affects grub2, enterprise linux. Severity is medium (CVSS 5.3). 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

Q: How urgent is CVE-2023-4693?

Priority 39/100. Public exploit reference; On your watchlist

Routine

MEDIUM 5.3WATCHLISTUPGRADEMITIGATE

CVE-2023-4693 is a medium-severity flaw (CVSS 5.3) affecting grub2, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Local
Attack complexity	High
Privileges needed	High
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-125
Published	2023-10-25
Last modified	2026-11-02

Publisher (CNA): Red Hat, Inc. · Vendor: gnu · redhat

Last updated 2026-11-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-10-25 18:17 UTCPublished CVE record published
2026-11-02 23:17 UTCUpdated Record last modified

gnu grub2 UPGRADE

Affected: < 2.12

Fixed in: 2.12

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy grub2 || rpm -q grub2 || grub2 --version

2. UPGRADE to 2.12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade grub2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade grub2

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat enterprise linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-4693?

grub2: upgrade to 2.12; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-4693 being exploited?

CVE-2023-4693 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-4693 affect?

CVE-2023-4693 affects grub2, enterprise linux. Severity is medium (CVSS 5.3). 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

How urgent is CVE-2023-4693?

Priority 39/100. Public exploit reference; On your watchlist

Related CVEs

CVE-2025-1125 HIGH 7.8 UPGRADE When reading data from a hfs filesystem, grub's hfs filesystem module uses user-controlled parameters from the
CVE-2025-0689 HIGH 7.8 UPGRADE When reading data from disk, the grub's UDF filesystem module utilizes the user controlled data length metadat
CVE-2025-0686 MEDIUM 6.4 UPGRADE A flaw was found in grub2
CVE-2025-0685 MEDIUM 6.4 UPGRADE A flaw was found in grub2
CVE-2025-0684 MEDIUM 6.4 UPGRADE A flaw was found in grub2

References

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