# CVE-2021-47433: btrfs: fix abort logic in btrfs_replace_file_extents

> A logic error in the Linux kernel's btrfs filesystem can lead to file system corruption and missing extents during specific operations.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47433, GHSA-6x3x-fg57-3vcm, UBUNTU-CVE-2021-47433

## What is CVE-2021-47433?

CVE-2021-47433 is a high-severity vulnerability in Linux kernel, published on 22 May 2024. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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

btrfs: fix abort logic in btrfs_replace_file_extents

Error injection testing uncovered a case where we'd end up with a
corrupt file system with a missing extent in the middle of a file.  This
occurs because the if statement to decide if we should abort is wrong.

The only way we would abort in this case is if we got a ret !=
-EOPNOTSUPP and we called from the file clone code.  However the
prealloc code uses this path too.  Instead we need to abort if there is
an error, and the only error we _don't_ abort on is -EOPNOTSUPP and only
if we came from the clone file code.

## Which versions are affected by CVE-2021-47433?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47433?

Apply the vendor's patch.

## Is CVE-2021-47433 being exploited?

There is no known exploitation of CVE-2021-47433 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-2021-47433 and fix it if it is affected.

What it is: CVE-2021-47433 is a high-severity vulnerability in Linux kernel, published on 22 May 2024. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-47433 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-2021-47433/ (Markdown: https://insights.sbomify.com/CVE-2021-47433/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47433
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47433
- OSV: https://osv.dev/vulnerability/CVE-2021-47433

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47433/
Summaries are generated and may contain mistakes; the official description above is the record.