# CVE-2024-56721: x86/CPU/AMD: Terminate the erratum_1386_microcode array

> A missing null terminator in an AMD CPU erratum array causes out-of-bounds reads, potentially leading to system crashes or information leaks.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Dec 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-56721, DEBIAN-CVE-2024-56721, GHSA-4hrg-cvr4-ff8f, UBUNTU-CVE-2024-56721

## What is CVE-2024-56721?

CVE-2024-56721 is a high-severity memory corruption vulnerability in Linux kernel, published on 29 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

x86/CPU/AMD: Terminate the erratum_1386_microcode array

The erratum_1386_microcode array requires an empty entry at the end.
Otherwise x86_match_cpu_with_stepping() will continue iterate the array after
it ended.

Add an empty entry to erratum_1386_microcode to its end.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2024-56721?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-56721?

Apply the vendor's patch.

## Is CVE-2024-56721 being exploited?

There is no known exploitation of CVE-2024-56721 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-56721 and fix it if it is affected.

What it is: CVE-2024-56721 is a high-severity memory corruption vulnerability in Linux kernel, published on 29 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-56721 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-56721/ (Markdown: https://insights.sbomify.com/CVE-2024-56721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56721
- OSV: https://osv.dev/vulnerability/CVE-2024-56721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-56721/
Summaries are generated and may contain mistakes; the official description above is the record.