# CVE-2026-46256: NFS/localio: prevent direct reclaim recursion into NFS via nfs_writepages

> A deadlock in Linux kernel NFS LOCALIO can cause system hangs during memory reclaim, requiring a patch to fix.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Jun 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BELL-CVE-2026-46256, DEBIAN-CVE-2026-46256, GHSA-44f9-rxj6-p8rg, ROOT-OS-DEBIAN-13-CVE-2026-46256, UBUNTU-CVE-2026-46256

## What is CVE-2026-46256?

CVE-2026-46256 is a medium-severity denial of service vulnerability in Linux kernel, published on 3 Jun 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:

NFS/localio: prevent direct reclaim recursion into NFS via nfs_writepages

LOCALIO is an NFS loopback mount optimization that avoids using the
network for READ, WRITE and COMMIT if the NFS client and server are
determined to be on the same system. But because LOCALIO is still
fundamentally "just NFS loopback mount" it is susceptible to recursion
deadlock via direct reclaim, e.g.: NFS LOCALIO down to XFS and then
back into NFS via nfs_writepages.

Fix LOCALIO's potential for direct reclaim deadlock by ensuring that
all its page cache allocations are done from GFP_NOFS context.

Thanks to Ben Coddington for pointing out commit ad22c7a043c2 ("xfs:
prevent stack overflows from page cache allocation").

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-46256?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46256?

Apply the vendor's patch.

## Is CVE-2026-46256 being exploited?

There is no known exploitation of CVE-2026-46256 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-46256 and fix it if it is affected.

What it is: CVE-2026-46256 is a medium-severity denial of service vulnerability in Linux kernel, published on 3 Jun 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-2026-46256 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-46256/ (Markdown: https://insights.sbomify.com/CVE-2026-46256/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46256
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46256
- OSV: https://osv.dev/vulnerability/CVE-2026-46256

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46256/
Summaries are generated and may contain mistakes; the official description above is the record.