# CVE-2026-74542: netfs: Fix folio_queue ENOMEM in writeback by adding a mempool

> A memory allocation failure in the Linux kernel netfs writeback path can trigger a warning and potential 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:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-74542, DEBIAN-CVE-2026-74542, GHSA-6qrf-jjmp-5pjw, UBUNTU-CVE-2026-74542

## What is CVE-2026-74542?

CVE-2026-74542 is a denial of service 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:

netfs: Fix folio_queue ENOMEM in writeback by adding a mempool

Fix the handling of folio_queue allocation failure in writeback by adding a
mempool and passing in gfp_t flags to the rolling buffer functions that
allocate memory, using the mempool if gfp != GFP_KERNEL.

This is then extended upwards and the gfp to be used for a request is stored
in the netfs_io_request struct and is then used for both requests and
subrequests, eliminating the sleeping loops there.

The failure caused:

    folio != NULL
    WARNING: fs/netfs/write_issue.c:603 at netfs_writepages+0x883/0xa10 fs/netfs/write_issue.c:603, CPU#3: syz.0.17/5919

## Which versions are affected by CVE-2026-74542?


## How do I fix CVE-2026-74542?

Apply the vendor's patch.

## Is CVE-2026-74542 being exploited?

There is no known exploitation of CVE-2026-74542 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74542 and fix it if it is affected.

What it is: CVE-2026-74542 is a denial of service 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-2026-74542 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-2026-74542/ (Markdown: https://insights.sbomify.com/CVE-2026-74542/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74542
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74542
- OSV: https://osv.dev/vulnerability/CVE-2026-74542

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74542/
Summaries are generated and may contain mistakes; the official description above is the record.