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CVE Record

CVE-2023-4692: Grub2: out-of-bounds write at fs/ntfs.c may lead to unsigned code execution

An out-of-bounds write flaw was found in grub2's NTFS filesystem driver. This issue may allow an attacker to present a specially crafted NTFS filesystem image, leading to grub's heap metadata corruption. In some circumstances, the attack may also corrupt the UEFI firmware heap metadata. As a result, arbitrary code execution and secure boot protection bypass may be achieved.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2023-4692 is a GRUB2 bootloader flaw in NTFS filesystem handling. A crafted NTFS filesystem image can corrupt heap memory during boot. In some conditions, this could allow unsigned code execution and bypass Secure Boot protections, making it relevant to boot-chain trust rather than ordinary remote server exposure.

Executive priority

High priority, but not an internet-wide emergency based on the provided evidence. Schedule remediation through normal high-severity patch governance, with faster action for laptops, shared systems, dual-boot hosts, kiosks, or environments where local administrative or physical access is harder to control.

Technical view

The issue is an out-of-bounds write in GRUB2's NTFS driver, mapped to CWE-122. Sources describe heap metadata corruption in GRUB and, in some circumstances, UEFI firmware heap corruption. The listed CVSS is 7.5 with local attack vector, high complexity, high privileges, changed scope, and high confidentiality, integrity, and availability impact.

Likely exposure

Likely exposure is systems using affected GRUB2 packages, including listed Red Hat Enterprise Linux 7, 8, and 9 grub2 packages, or GRUB 2.12 where NTFS filesystem handling is reachable during boot. Exposure depends on boot configuration and attacker ability to present crafted local media or filesystem content.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation is not described as remote; the CVSS vector requires local access, high privileges, and high complexity. The business concern is the potential Secure Boot bypass and code execution before the operating system fully controls the platform.

Researcher notes

Focus analysis on GRUB2 NTFS parsing in fs/ntfs.c and heap metadata corruption during pre-OS execution. Avoid assuming exploit availability: the provided sources support impact potential, not active exploitation. Validation should be package and boot-path focused, with vendor advisory tracking for exact fixed builds.

Mitigation direction

  • Apply vendor GRUB2 updates from applicable advisories, including Red Hat RHSA-2024:2456 and RHSA-2024:3184.
  • Check distribution advisories for Fedora, Debian, Gentoo, NetApp, or other affected environments before patching.
  • Restrict unauthorized boot media, boot-order changes, and administrative access to boot partitions.
  • Review Secure Boot and firmware update guidance from the system or OS vendor.
  • Prioritize systems where physical or administrative local access is plausible.

Validation and detection

  • Inventory GRUB2 package versions and compare them with the affected versions listed by vendor advisories.
  • Confirm whether NTFS filesystem support is present or reachable in the GRUB boot path.
  • Verify updated GRUB2 packages and bootloader artifacts are actually installed after patching.
  • Review endpoint controls for removable media, firmware settings, and boot-order modification.
  • Track vendor advisories for additional affected builds or remediation notes.
Prepared
Confidence
high
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-122: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2023-4692 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
5Timeline events
2ADP providers
14Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H0.86redhat

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2023-4692Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineredhat

    Reported to Red Hat.

  2. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Unknown vendorgrubgrub, 2.12Listed
Red HatRed Hat Enterprise Linux 8grub2, 1:2.02-156.el8affected
Red HatRed Hat Enterprise Linux 9grub2, 1:2.06-77.el9affected
Red HatRed Hat Enterprise Linux 7grub2affected
Weakness

CWE details

CWE-122

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.