# CVE-2026-89710: NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path

> A memory leak in the Linux kernel's NFSv4.1 implementation allows remote attackers to cause a denial of service by exhausting kernel memory.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100508, BELL-CVE-2026-89710, DEBIAN-CVE-2026-89710, GHSA-84pc-7mxq-h2j8, UBUNTU-CVE-2026-89710

## What is CVE-2026-89710?

CVE-2026-89710 is a memory corruption vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path

When the server returns a new layout stateid while a valid one is still
held, pnfs_layout_process() calls pnfs_mark_matching_lsegs_return() on
the on-stack free_me list and jumps to out_forget. Segments whose
reference count drops to zero are unlinked from lo->plh_segs and moved
to free_me by mark_lseg_invalid(); for an idle cached segment the layout
header holds the only reference, so this happens on the first decrement.

out_forget never drains free_me -- only the success path calls
pnfs_free_lseg_list().

Commit 814b84971388 ("pNFS/NFSv4: Fix a layout segment leak in
pnfs_layout_process()") added the drain; commit 08bd8dbe8882
("pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()")
removed it while switching the destination to lo->plh_return_segs, which
is drained elsewhere. Commit fb700ef02676 ("NFSv4.1: Simplify layout
return in pnfs_layout_process()") switched the destination back to
free_me without restoring the drain.

Restore the pnfs_free_lseg_list() call.

## Which versions are affected by CVE-2026-89710?


## How do I fix CVE-2026-89710?

Apply the vendor's patch.

## Is CVE-2026-89710 being exploited?

There is no known exploitation of CVE-2026-89710 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89710 and fix it if it is affected.

What it is: CVE-2026-89710 is a memory corruption vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89710 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-2026-89710/ (Markdown: https://insights.sbomify.com/CVE-2026-89710/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89710
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89710
- OSV: https://osv.dev/vulnerability/CVE-2026-89710

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89710/
Summaries are generated and may contain mistakes; the official description above is the record.