# CVE-2026-93211: nfsd: initialize DRC hash table before registering shrinker

> A race condition in the Linux kernel NFS server can cause a null pointer dereference and system crash when the DRC hash table is accessed before initialization.

- **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:** 24 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-93211, DEBIAN-CVE-2026-93211, GHSA-4vgq-cgvq-hg3w, UBUNTU-CVE-2026-93211

## What is CVE-2026-93211?

CVE-2026-93211 is a vulnerability in Linux, published on 24 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:

nfsd: initialize DRC hash table before registering shrinker

shrinker_register() precedes the INIT_LIST_HEAD loop and the
drc_hashsize store. On weakly-ordered architectures (arm64, ppc),
a shrinker scan can observe drc_hashsize before the bucket list
heads are initialized, causing a NULL deref in the DRC shrinker
callback.

Move bucket initialization and the drc_hashsize store before
shrinker_register() so the hash table is fully initialized before
it becomes visible to the shrinker.

## Which versions are affected by CVE-2026-93211?


## How do I fix CVE-2026-93211?

Apply the vendor's patch.

## Is CVE-2026-93211 being exploited?

There is no known exploitation of CVE-2026-93211 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93211 and fix it if it is affected.

What it is: CVE-2026-93211 is a vulnerability in Linux, published on 24 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-2026-93211 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-2026-93211/ (Markdown: https://insights.sbomify.com/CVE-2026-93211/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93211
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93211
- OSV: https://osv.dev/vulnerability/CVE-2026-93211

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93211/
Summaries are generated and may contain mistakes; the official description above is the record.