# CVE-2026-72440: md/raid1: fix writes_pending and barrier reference leaks on write failures

> A bug in the Linux kernel's RAID1 driver causes resource leaks on write failures, potentially leading to a denial of service.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/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:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-96588, BELL-CVE-2026-72440, DEBIAN-CVE-2026-72440, GHSA-jh9h-wfxq-pfm4, UBUNTU-CVE-2026-72440

## What is CVE-2026-72440?

CVE-2026-72440 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. 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:

md/raid1: fix writes_pending and barrier reference leaks on write failures

raid1_make_request() acquires a writes_pending reference with
md_write_start() before calling raid1_write_request(). Several failure
paths in raid1_write_request() complete the bio and return without
reaching the normal write completion path, causing the corresponding
md_write_end() to be skipped.

Make raid1_write_request() return a status indicating whether the write
request was successfully queued. This allows raid1_make_request() to
call md_write_end() when raid1_write_request() fails.

Additionally, if wait_blocked_rdev() fails after wait_barrier()
succeeds, the associated barrier reference is not released.

Call allow_barrier() before returning from that path to keep the barrier
accounting balanced.

## Which versions are affected by CVE-2026-72440?


## How do I fix CVE-2026-72440?

Apply the vendor's patch.

## Is CVE-2026-72440 being exploited?

There is no known exploitation of CVE-2026-72440 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72440 and fix it if it is affected.

What it is: CVE-2026-72440 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72440 in the wild and no public exploit code.

Affected product: Linux. 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-2026-72440/ (Markdown: https://insights.sbomify.com/CVE-2026-72440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72440
- OSV: https://osv.dev/vulnerability/CVE-2026-72440

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72440/
Summaries are generated and may contain mistakes; the official description above is the record.