# CVE-2026-97972: net: macb: put the "mdio" child node reference on success

> A reference counting bug in the Linux kernel macb network driver causes a memory leak, potentially leading to 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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-97972, DEBIAN-CVE-2026-97972, GHSA-234h-4jcx-ffp3, UBUNTU-CVE-2026-97972

## What is CVE-2026-97972?

CVE-2026-97972 is a memory corruption vulnerability in Linux, published on 25 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:

net: macb: put the "mdio" child node reference on success

macb_mii_init() holds the reference returned by of_get_child_by_name()
for macb_mdiobus_register() and drops it only on the error paths, so
every successful probe leaks a node reference. On a CM5, overlay
removal after four bind cycles reports

  OF: ERROR: memory leak, expected refcount 1 instead of 5

Drop the reference after registration, where __mdiobus_register() has
already taken its own for the lifetime of the bus.

## Which versions are affected by CVE-2026-97972?


## How do I fix CVE-2026-97972?

Apply the vendor's patch.

## Is CVE-2026-97972 being exploited?

There is no known exploitation of CVE-2026-97972 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97972 and fix it if it is affected.

What it is: CVE-2026-97972 is a memory corruption vulnerability in Linux, published on 25 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-2026-97972 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-2026-97972/ (Markdown: https://insights.sbomify.com/CVE-2026-97972/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97972
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97972
- OSV: https://osv.dev/vulnerability/CVE-2026-97972

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97972/
Summaries are generated and may contain mistakes; the official description above is the record.