# CVE-2026-43359: btrfs: fix transaction abort on set received ioctl due to item overflow

> A local user can trigger a filesystem read-only state by exploiting an item overflow in the btrfs set received ioctl, causing denial of service.

- **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:** 8 May 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-43359, DEBIAN-CVE-2026-43359, GHSA-63hq-hrgx-pfwm, ROOT-OS-DEBIAN-11-CVE-2026-43359, ROOT-OS-UBUNTU-2204-CVE-2026-43359, ROOT-OS-UBUNTU-2404-CVE-2026-43359, UBUNTU-CVE-2026-43359

## What is CVE-2026-43359?

CVE-2026-43359 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 May 2026. 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: fix transaction abort on set received ioctl due to item overflow

If the set received ioctl fails due to an item overflow when attempting to
add the BTRFS_UUID_KEY_RECEIVED_SUBVOL we have to abort the transaction
since we did some metadata updates before.

This means that if a user calls this ioctl with the same received UUID
field for a lot of subvolumes, we will hit the overflow, trigger the
transaction abort and turn the filesystem into RO mode. A malicious user
could exploit this, and this ioctl does not even requires that a user
has admin privileges (CAP_SYS_ADMIN), only that he/she owns the subvolume.

Fix this by doing an early check for item overflow before starting a
transaction. This is also race safe because we are holding the subvol_sem
semaphore in exclusive (write) mode.

A test case for fstests will follow soon.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound))

## Which versions are affected by CVE-2026-43359?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43359?

Apply the vendor's patch.

## Is CVE-2026-43359 being exploited?

There is no known exploitation of CVE-2026-43359 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-2026-43359 and fix it if it is affected.

What it is: CVE-2026-43359 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 May 2026. 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-2026-43359 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-2026-43359/ (Markdown: https://insights.sbomify.com/CVE-2026-43359/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43359
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43359
- OSV: https://osv.dev/vulnerability/CVE-2026-43359

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43359/
Summaries are generated and may contain mistakes; the official description above is the record.