# CVE-2026-74334: RDMA/nldev: Fix locking when accessing mr->pd

> A race condition in the Linux kernel RDMA subsystem allows unsafe access to memory region protection domains, potentially leading to undefined behavior.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-96486, BELL-CVE-2026-74334, DEBIAN-CVE-2026-74334, GHSA-g8r2-wj85-rq7q, UBUNTU-CVE-2026-74334

## What is CVE-2026-74334?

CVE-2026-74334 is a high-severity vulnerability in Linux, published on 15 Aug 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/nldev: Fix locking when accessing mr->pd

Sashiko points out that, due to rereg_mr, the PD is actually variable and
all the touches in nldev are racy.

Use mr->device instead of mr->pd->device.

Getting the PD restrack ID is more tricky. To avoid disturbing all the
happy paths, add an rdma_restrack_sync() operation which is sort of like
flush_workqueue() or synchronize_irq(): after it returns, all the old
nldev touches to the mr are gone and everything sees the new PD. This
makes it safe to reach into the PD pointer.

## Which versions are affected by CVE-2026-74334?


## How do I fix CVE-2026-74334?

Apply the vendor's patch.

## Is CVE-2026-74334 being exploited?

There is no known exploitation of CVE-2026-74334 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74334 and fix it if it is affected.

What it is: CVE-2026-74334 is a high-severity vulnerability in Linux, published on 15 Aug 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-2026-74334 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-2026-74334/ (Markdown: https://insights.sbomify.com/CVE-2026-74334/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74334
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74334
- OSV: https://osv.dev/vulnerability/CVE-2026-74334

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74334/
Summaries are generated and may contain mistakes; the official description above is the record.