# CVE-2026-72437: md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry

> A memory leak in the Linux kernel RAID1 driver can lead to resource exhaustion and denial of service when handling blocked read retries.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72437, DEBIAN-CVE-2026-72437, GHSA-hcmp-m525-ffjq, UBUNTU-CVE-2026-72437

## What is CVE-2026-72437?

CVE-2026-72437 is a memory corruption vulnerability in Linux, published on 15 Aug 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/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry

When a read is retried, raid1_read_request() may be called with a
pre-allocated r1_bio. If wait_read_barrier() fails for a REQ_NOWAIT
read, the bio is completed and the function returns immediately. In this
case the existing r1_bio is leaked.

This fixes a leak of pre-allocated r1_bio structures for retried reads.

## Which versions are affected by CVE-2026-72437?


## How do I fix CVE-2026-72437?

Apply the vendor's patch.

## Is CVE-2026-72437 being exploited?

There is no known exploitation of CVE-2026-72437 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72437 and fix it if it is affected.

What it is: CVE-2026-72437 is a memory corruption vulnerability in Linux, published on 15 Aug 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-2026-72437 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-2026-72437/ (Markdown: https://insights.sbomify.com/CVE-2026-72437/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72437
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72437
- OSV: https://osv.dev/vulnerability/CVE-2026-72437

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72437/
Summaries are generated and may contain mistakes; the official description above is the record.