# CVE-2026-98564: net: dsa: mt7530: leave the MDIO IRQ mappings to regmap-irq

> A race condition in the mt7530 DSA driver causes a null pointer dereference during device removal, leading to a kernel crash.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98564, DEBIAN-CVE-2026-98564, GHSA-843v-cg64-5wvw, UBUNTU-CVE-2026-98564

## What is CVE-2026-98564?

CVE-2026-98564 is a vulnerability in Linux, published on 18 Oct 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: dsa: mt7530: leave the MDIO IRQ mappings to regmap-irq

mt7530_remove_common() disposes the per-PHY interrupt mappings from
.remove, but the regmap-irq chip that owns the domain is devm-registered,
so its parent interrupt is only freed once .remove has returned. The
switch's own regmap-irq thread can therefore still dispatch on a mapping
that is already gone: irq_find_mapping() returns 0, irq_to_desc() returns
NULL and handle_nested_irq() locks desc->lock without checking it. The
attached PHYs have not given those interrupts back yet either, which the
kernel warns about a moment before the fault.

regmap_del_irq_chip() disposes the same mappings itself, after freeing the
parent interrupt and before removing the domain, so there is nothing left
for the driver to do here. Until it runs the descriptors stay alive, and a
late dispatch on one of them is harmless: dsa_unregister_switch() has freed
the PHY handlers by then, so handle_nested_irq() finds no action and
returns.

## Which versions are affected by CVE-2026-98564?


## How do I fix CVE-2026-98564?

Apply the vendor's patch.

## Is CVE-2026-98564 being exploited?

There is no known exploitation of CVE-2026-98564 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98564 and fix it if it is affected.

What it is: CVE-2026-98564 is a vulnerability in Linux, published on 18 Oct 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-2026-98564 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-2026-98564/ (Markdown: https://insights.sbomify.com/CVE-2026-98564/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98564
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98564
- OSV: https://osv.dev/vulnerability/CVE-2026-98564

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98564/
Summaries are generated and may contain mistakes; the official description above is the record.