# CVE-2026-31621: bnge: return after auxiliary_device_uninit() in error path

> A missing return statement in the bnge driver error path causes a null pointer dereference, leading to a kernel crash.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 24 Apr 2026
- **Updated:** 14 Jun 2026
- **Also known as:** AZL-84023, DEBIAN-CVE-2026-31621, GHSA-jq95-p6v7-8mxr, UBUNTU-CVE-2026-31621

## What is CVE-2026-31621?

CVE-2026-31621 is a medium-severity vulnerability in Linux kernel, published on 24 Apr 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:

bnge: return after auxiliary_device_uninit() in error path

When auxiliary_device_add() fails, the error block calls
auxiliary_device_uninit() but does not return.  The uninit drops the
last reference and synchronously runs bnge_aux_dev_release(), which sets
bd->auxr_dev = NULL and frees the underlying object.  The subsequent
bd->auxr_dev->net = bd->netdev then dereferences NULL, which is not a
good thing to have happen when trying to clean up from an error.

Add the missing return, as the auxiliary bus documentation states is a
requirement (seems that LLM tools read documentation better than humans
do...)

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-31621?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31621?

Apply the vendor's patch.

## Is CVE-2026-31621 being exploited?

There is no known exploitation of CVE-2026-31621 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31621 and fix it if it is affected.

What it is: CVE-2026-31621 is a medium-severity vulnerability in Linux kernel, published on 24 Apr 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-2026-31621 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-31621/ (Markdown: https://insights.sbomify.com/CVE-2026-31621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31621
- OSV: https://osv.dev/vulnerability/CVE-2026-31621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31621/
Summaries are generated and may contain mistakes; the official description above is the record.