CVE-2023-4693 | Grub2: out-of-bounds read at fs/ntfs.c

Exp

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.

Published: 2023-10-25 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4693 is rated Exploit Available (50.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.50%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-4693

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-4693

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.01% 0.50% +0.49%
2 2025-11-21 0.07% 0.01% -0.06%
3 2025-11-18 — 0.07% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4693

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 0.8 4.0 [email protected]
4.6 3.1 MEDIUM
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 0.9 3.6 [email protected]

Weakness enumeration for CVE-2023-4693

OS Trackers for CVE-2023-4693

vendor priority summary link
debian not yet assigned CVE-2023-4693 not yet assigned priority: Debian including 1 source packages (grub2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-4693
redhat low — https://access.redhat.com/security/cve/CVE-2023-4693
suse medium CVE-2023-4693 severity moderate: SUSE including 401 source package names (1.2.3-2.2.63:grub2-2.06-150400.11.38.1, 1.2.3-2.2.63:grub2-i386-pc-2.06-150400.11.38.1, …), 1141 product×package rows across 215 product lines (Container rancher/elemental-teal-rt/5.4, Container rancher/elemental-teal/5.4, … (215 product lines)): Fixed 961, Known Affected 180. https://www.suse.com/security/cve/CVE-2023-4693/
ubuntu medium CVE-2023-4693 medium priority: Ubuntu including 3 source packages (grub2, grub2-signed, grub2-unsigned), 36 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 15, released 12, needs-triage 6, ignored 3. https://ubuntu.com/security/CVE-2023-4693

Affected software / configurations for CVE-2023-4693

Vendor Product Version Raw CPE
gnu grub2 < 2.12 cpe:2.3:a:gnu:grub2:*:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

References for CVE-2023-4693

URL Tags
https://access.redhat.com/errata/RHSA-2024:2456
https://access.redhat.com/errata/RHSA-2024:3184
https://access.redhat.com/security/cve/CVE-2023-4693 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2238343 Issue Tracking Third Party Advisory
https://dfir.ru/2023/10/03/cve-2023-4692-cve-2023-4693-vulnerabilities-in-the-grub-boot-manager/ Exploit Third Party Advisory
https://lists.gnu.org/archive/html/grub-devel/2023-10/msg00028.html Mailing List
https://seclists.org/oss-sec/2023/q4/37 Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/10/msg00007.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/FUU42E7CPYLATXOYVYNW6YTXXULAOV6L/
https://lists.fedoraproject.org/archives/list/[email protected]/message/OIRJ5UZRXX2KLR4IKBJEQUNGOCXMMDLY/
https://lists.fedoraproject.org/archives/list/[email protected]/message/PERFILCHFEUGG3OAMC6W55P6DDIBZK4Q/
https://security.gentoo.org/glsa/202311-14
https://security.netapp.com/advisory/ntap-20231208-0002/
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