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

> An out-of-bounds write in GRUB2's NTFS driver allows attackers to execute arbitrary code and bypass Secure Boot via a crafted filesystem image.

- **Severity:** High 7.5 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Oct 2023
- **Updated:** 21 Jul 2026
- **Also known as:** AZL-31686, AZL-34795, BELL-CVE-2023-4692, CLSA-2023-1700161520, CLSA-2023-1700164193, CLSA-2024-1707226462, CLSA-2026-1779219098, DEBIAN-CVE-2023-4692, GHSA-6w7h-fpm5-3ww6, UBUNTU-CVE-2023-4692

## What is CVE-2023-4692?

CVE-2023-4692 is a high-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 25 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2023-4692?

It affects 2 products.


Products: Gnu Grub2, Redhat Enterprise Linux.

## How do I fix CVE-2023-4692?

Apply the vendor's patch.

## Is CVE-2023-4692 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-4692 exists.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2024-56737](https://insights.sbomify.com/CVE-2024-56737/): Memory corruption in GRUB2 (high 8.8)
- [CVE-2022-28733](https://insights.sbomify.com/CVE-2022-28733/): Integer underflow in grub_net_recv_ip4_packets (high 8.1)
- [CVE-2022-28734](https://insights.sbomify.com/CVE-2022-28734/): Out-of-bounds write when handling split HTTP headers (high 8.1)
- [CVE-2025-61662](https://insights.sbomify.com/CVE-2025-61662/): Grub2: missing unregister call for gettext command may lead to use-after-free (high 7.8)
- [CVE-2024-45782](https://insights.sbomify.com/CVE-2024-45782/): Grub2: fs/hfs: strcpy() using the volume name (fs/hfs.c:382) (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-4692 and fix it if it is affected.

What it is: CVE-2023-4692 is a high-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 25 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-4692 exists.

Affected product: Redhat Enterprise Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-4692/ (Markdown: https://insights.sbomify.com/CVE-2023-4692/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4692
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4692
- OSV: https://osv.dev/vulnerability/CVE-2023-4692

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4692/
Summaries are generated and may contain mistakes; the official description above is the record.