# CVE-2026-89798: rpcrdma: arm rn_done before publishing the notification

> A race condition in the Linux kernel's RPC RDMA module allows a null pointer dereference during device removal, causing a 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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89798, DEBIAN-CVE-2026-89798, GHSA-rf2c-8wjw-q46f, UBUNTU-CVE-2026-89798

## What is CVE-2026-89798?

CVE-2026-89798 is a vulnerability in Linux, published on 16 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:

rpcrdma: arm rn_done before publishing the notification

rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before
storing the caller's callback in rn->rn_done. The xarray makes @rn
reachable to rpcrdma_remove_one(), which walks rd_xa and invokes
rn->rn_done(rn) for every registered notification. A device removal
that races a fresh registration can therefore observe @rn with
rn_done still NULL, because the notification objects are zero
allocated by their owners, and call through a NULL function pointer.

Store rn->rn_done before xa_alloc() publishes @rn. The xarray's
store-side and load-side ordering then guarantees that any CPU which
finds @rn in rd_xa also observes the armed callback.

rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel
for a completed registration, so the early store must not survive a
failed registration. Clear rn_done again when xa_alloc() fails.
Were it left set, the failed-accept cleanup path would call
rpcrdma_rn_unregister() on an @rn that was never inserted, erasing
an unrelated rd_xa slot and underflowing rd_kref.

## Which versions are affected by CVE-2026-89798?


## How do I fix CVE-2026-89798?

Apply the vendor's patch.

## Is CVE-2026-89798 being exploited?

There is no known exploitation of CVE-2026-89798 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89798 and fix it if it is affected.

What it is: CVE-2026-89798 is a vulnerability in Linux, published on 16 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-2026-89798 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-2026-89798/ (Markdown: https://insights.sbomify.com/CVE-2026-89798/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89798
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89798
- OSV: https://osv.dev/vulnerability/CVE-2026-89798

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89798/
Summaries are generated and may contain mistakes; the official description above is the record.