# CVE-2024-42231: btrfs: zoned: fix calc_available_free_space() for zoned mode

> Incorrect space calculation in btrfs zoned mode can cause premature ENOSPC errors, leading to denial of service on nearly full filesystems.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 30 Jul 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-42231, DEBIAN-CVE-2024-42231, GHSA-hmvx-mw63-jvg7, UBUNTU-CVE-2024-42231

## What is CVE-2024-42231?

CVE-2024-42231 is a medium-severity denial of service vulnerability in Linux kernel, published on 30 Jul 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:

btrfs: zoned: fix calc_available_free_space() for zoned mode

calc_available_free_space() returns the total size of metadata (or
system) block groups, which can be allocated from unallocated disk
space. The logic is wrong on zoned mode in two places.

First, the calculation of data_chunk_size is wrong. We always allocate
one zone as one chunk, and no partial allocation of a zone. So, we
should use zone_size (= data_sinfo->chunk_size) as it is.

Second, the result "avail" may not be zone aligned. Since we always
allocate one zone as one chunk on zoned mode, returning non-zone size
aligned bytes will result in less pressure on the async metadata reclaim
process.

This is serious for the nearly full state with a large zone size device.
Allowing over-commit too much will result in less async reclaim work and
end up in ENOSPC. We can align down to the zone size to avoid that.

Weakness: CWE-682 (Incorrect Calculation)

## Which versions are affected by CVE-2024-42231?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-42231?

Apply the vendor's patch.

## Is CVE-2024-42231 being exploited?

There is no known exploitation of CVE-2024-42231 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-2024-42231 and fix it if it is affected.

What it is: CVE-2024-42231 is a medium-severity denial of service vulnerability in Linux kernel, published on 30 Jul 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-2024-42231 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-2024-42231/ (Markdown: https://insights.sbomify.com/CVE-2024-42231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-42231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-42231
- OSV: https://osv.dev/vulnerability/CVE-2024-42231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-42231/
Summaries are generated and may contain mistakes; the official description above is the record.