# CVE-2026-89506: RDMA/uverbs: Add UVERBS_ATTR_UHW to UVERBS_METHOD_REG_MR

> A malicious local user can trigger a kernel crash in RDMA drivers by passing invalid user hardware data, causing 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-2026-89506, DEBIAN-CVE-2026-89506, GHSA-pfq2-9rm7-2x65, UBUNTU-CVE-2026-89506

## What is CVE-2026-89506?

CVE-2026-89506 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/uverbs: Add UVERBS_ATTR_UHW to UVERBS_METHOD_REG_MR

The original commit missed that three drivers (mthca, irdma, siw) have UHW
data associated with reg_mr that cannot be passed through the ioctl. They
also assume that the udata cannot be NULL, so failing to pass a valid
udata can trigger a NULL udata crash in those drivers.

This never happens in real systems since in rdma-core ibv_cmd_reg_mr_ex()
does not accept a udata and those three drivers don't use it, however a
malicious userspace could trigger it.

## Which versions are affected by CVE-2026-89506?


## How do I fix CVE-2026-89506?

Apply the vendor's patch.

## Is CVE-2026-89506 being exploited?

There is no known exploitation of CVE-2026-89506 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89506 and fix it if it is affected.

What it is: CVE-2026-89506 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-2026-89506 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-2026-89506/ (Markdown: https://insights.sbomify.com/CVE-2026-89506/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89506
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89506
- OSV: https://osv.dev/vulnerability/CVE-2026-89506

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89506/
Summaries are generated and may contain mistakes; the official description above is the record.