# CVE-2026-72370: iomap: release pages on atomic dio size mismatch

> A memory leak in the Linux kernel's iomap subsystem can lead to resource exhaustion and denial of service when handling atomic direct I/O size mismatches.

- **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:** 15 Oct 2026
- **Also known as:** BELL-CVE-2026-72370, DEBIAN-CVE-2026-72370, GHSA-mf8w-m9qx-f6j9, UBUNTU-CVE-2026-72370

## What is CVE-2026-72370?

CVE-2026-72370 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:

iomap: release pages on atomic dio size mismatch

If bio_iov_iter_get_pages() or the bounce helper succeeds but builds a
short bio, the REQ_ATOMIC size check rejects it before submission.  The
old error path only dropped the bio reference, leaving any pages already
attached to the bio unreleased.

Release or unbounce the pages before falling through to out_put_bio on
this error path.

This bug was reported by sashiko:
https://sashiko.dev/#/patchset/20260608073134.95964-1-changfengnan%40bytedance.com

## Which versions are affected by CVE-2026-72370?


## How do I fix CVE-2026-72370?

Apply the vendor's patch.

## Is CVE-2026-72370 being exploited?

There is no known exploitation of CVE-2026-72370 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72370 and fix it if it is affected.

What it is: CVE-2026-72370 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-2026-72370 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-2026-72370/ (Markdown: https://insights.sbomify.com/CVE-2026-72370/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72370
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72370
- OSV: https://osv.dev/vulnerability/CVE-2026-72370

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72370/
Summaries are generated and may contain mistakes; the official description above is the record.