# CVE-2026-89509: RDMA/ionic: Embed counter driver data in rdma_counter allocation

> A missing driver adaptation in the Linux kernel RDMA/ionic driver causes a NULL pointer dereference, leading to a denial of service.

- **Severity:** Not scored
- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89509, DEBIAN-CVE-2026-89509, GHSA-p644-p7x2-xc3f, UBUNTU-CVE-2026-89509

## What is CVE-2026-89509?

CVE-2026-89509 is a vulnerability in Linux, published on 11 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:

RDMA/ionic: Embed counter driver data in rdma_counter allocation

Commit 7e53b31acc7f ("RDMA/core: Create and destroy rdma_counter using
rdma_zalloc_drv_obj()") requires drivers implementing counter ops to
embed struct rdma_counter in a driver-specific struct, register its size
via INIT_RDMA_OBJ_SIZE, and provide a counter_init callback.

The ionic driver was merged without this adaptation, causing a NULL
pointer dereference in alloc_and_bind() since rdma_zalloc_drv_obj()
allocates zero bytes when size_rdma_counter is unset.

Consolidate struct ionic_counter into a new struct ionic_rdma_counter
that embeds struct rdma_counter, replace the xarray with a lightweight
ida for ID allocation, and add the required counter_init and
INIT_RDMA_OBJ_SIZE declarations.

## Which versions are affected by CVE-2026-89509?


## How do I fix CVE-2026-89509?

Apply the vendor's patch.

## Is CVE-2026-89509 being exploited?

There is no known exploitation of CVE-2026-89509 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89509 and fix it if it is affected.

What it is: CVE-2026-89509 is a vulnerability in Linux, published on 11 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-2026-89509 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-2026-89509/ (Markdown: https://insights.sbomify.com/CVE-2026-89509/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89509
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89509
- OSV: https://osv.dev/vulnerability/CVE-2026-89509

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89509/
Summaries are generated and may contain mistakes; the official description above is the record.