# CVE-2026-43309: md raid: fix hang when stopping arrays with metadata through dm-raid

> A local attacker can cause a system hang by stopping a dm-raid managed RAID array, leading to a 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:** 21 Oct 2026
- **Also known as:** AZL-86124, BELL-CVE-2026-43309, DEBIAN-CVE-2026-43309, GHSA-v56g-44rc-67wq, ROOT-OS-DEBIAN-11-CVE-2026-43309, ROOT-OS-DEBIAN-12-CVE-2026-43309, ROOT-OS-DEBIAN-13-CVE-2026-43309, ROOT-OS-UBUNTU-2204-CVE-2026-43309, ROOT-OS-UBUNTU-2404-CVE-2026-43309, UBUNTU-CVE-2026-43309

## What is CVE-2026-43309?

CVE-2026-43309 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:

md raid: fix hang when stopping arrays with metadata through dm-raid

When using device-mapper's dm-raid target, stopping a RAID array can cause
the system to hang under specific conditions.

This occurs when:

- A dm-raid managed device tree is suspended from top to bottom
   (the top-level RAID device is suspended first, followed by its
    underlying metadata and data devices)

- The top-level RAID device is then removed

Removing the top-level device triggers a hang in the following sequence:
the dm-raid destructor calls md_stop(), which tries to flush the
write-intent bitmap by writing to the metadata sub-devices. However, these
devices are already suspended, making them unable to complete the write-intent
operations and causing an indefinite block.

Fix:

- Prevent bitmap flushing when md_stop() is called from dm-raid
destructor context
  and avoid a quiescing/unquescing cycle which could also cause I/O

- Still allow write-intent bitmap flushing when called from dm-raid
suspend context

This ensures that RAID array teardown can complete successfully even when the
underlying devices are in a suspended state.

This second patch uses md_is_rdwr() to distinguish between suspend and
destructor paths as elaborated on above.

## Which versions are affected by CVE-2026-43309?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43309?

Apply the vendor's patch.

## Is CVE-2026-43309 being exploited?

There is no known exploitation of CVE-2026-43309 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-2026-43309 and fix it if it is affected.

What it is: CVE-2026-43309 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-2026-43309 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-2026-43309/ (Markdown: https://insights.sbomify.com/CVE-2026-43309/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43309
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43309
- OSV: https://osv.dev/vulnerability/CVE-2026-43309

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43309/
Summaries are generated and may contain mistakes; the official description above is the record.