# CVE-2026-90384: iomap: release the folio batch on iomap callback failures

> A Linux kernel bug in iomap fails to release folio batches on error, potentially causing memory leaks or denial of service.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-90384, GHSA-7vw7-23g3-j252, UBUNTU-CVE-2026-90384

## What is CVE-2026-90384?

CVE-2026-90384 is a memory corruption vulnerability in Linux, published on 17 Sep 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 the folio batch on iomap callback failures

A sashiko review of an unrelated patch points out that the folio
batch mechanism used for iomap zero range fails to release the batch
in a couple error scenarios. If either calls to ->iomap_end() or
->iomap_begin() fail, the direct return paths bypass the batch
cleanup.

The ->iomap_end() case is not a practical issue at the moment
because there is no user of the mechanism that returns an error from
this path. The ->iomap_begin() case is theoretically possible
because XFS can invoke the fill helper and error out at various
points thereafter. This subtly complicates things because XFS does
not transfer iomap_flags to the iomap data structure in the error
path.

To deal with both of these issues, first make sure to invoke the
cleanup helper in the error path for either fs callback. Second,
update the helper to clear the flag unconditionally and release the
batch so long as it is populated. This more clearly delineates the
purpose of the flag to control the I/O path and not necessarily the
status of the fbatch, so add a comment around this as well.

## Which versions are affected by CVE-2026-90384?


## How do I fix CVE-2026-90384?

Apply the vendor's patch.

## Is CVE-2026-90384 being exploited?

There is no known exploitation of CVE-2026-90384 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90384 and fix it if it is affected.

What it is: CVE-2026-90384 is a memory corruption vulnerability in Linux, published on 17 Sep 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-2026-90384 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-2026-90384/ (Markdown: https://insights.sbomify.com/CVE-2026-90384/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90384
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90384
- OSV: https://osv.dev/vulnerability/CVE-2026-90384

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90384/
Summaries are generated and may contain mistakes; the official description above is the record.