# CVE-2021-47168: NFS: fix an incorrect limit in filelayout_decode_layout()

> An incorrect size limit in the Linux kernel NFS file layout decoder can cause memory corruption, potentially leading to code execution or system crashes.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47168, GHSA-8229-hhm6-4mmc, UBUNTU-CVE-2021-47168

## What is CVE-2021-47168?

CVE-2021-47168 is a critical memory corruption vulnerability in Linux kernel, published on 25 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

NFS: fix an incorrect limit in filelayout_decode_layout()

The "sizeof(struct nfs_fh)" is two bytes too large and could lead to
memory corruption.  It should be NFS_MAXFHSIZE because that's the size
of the ->data[] buffer.

I reversed the size of the arguments to put the variable on the left.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-47168?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47168?

Apply the vendor's patch.

## Is CVE-2021-47168 being exploited?

There is no known exploitation of CVE-2021-47168 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-2021-47168 and fix it if it is affected.

What it is: CVE-2021-47168 is a critical memory corruption vulnerability in Linux kernel, published on 25 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-47168 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-2021-47168/ (Markdown: https://insights.sbomify.com/CVE-2021-47168/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47168
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47168
- OSV: https://osv.dev/vulnerability/CVE-2021-47168

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47168/
Summaries are generated and may contain mistakes; the official description above is the record.