# CVE-2025-40076: PCI: rcar-host: Pass proper IRQ domain to generic_handle_domain_irq()

> A null pointer dereference in the Linux kernel PCI rcar-host driver causes a system crash when handling MSI interrupts.

- **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:** 28 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-40076, GHSA-6gg9-hc2m-2hw4, UBUNTU-CVE-2025-40076

## What is CVE-2025-40076?

CVE-2025-40076 is a vulnerability in Linux, published on 28 Oct 2025. 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:

PCI: rcar-host: Pass proper IRQ domain to generic_handle_domain_irq()

Starting with commit dd26c1a23fd5 ("PCI: rcar-host: Switch to
msi_create_parent_irq_domain()"), the MSI parent IRQ domain is NULL because
the object of type struct irq_domain_info passed to:

msi_create_parent_irq_domain() ->
  irq_domain_instantiate()() ->
    __irq_domain_instantiate()

has no reference to the parent IRQ domain. Using msi->domain->parent as an
argument for generic_handle_domain_irq() leads to below error:

	"Unable to handle kernel NULL pointer dereference at virtual address"

This error was identified while switching the upcoming RZ/G3S PCIe host
controller driver to msi_create_parent_irq_domain() (which was using a
similar pattern to handle MSIs (see link section)), but it was not tested
on hardware using the pcie-rcar-host controller driver due to lack of
hardware.

[mani: reworded subject and description]

## Which versions are affected by CVE-2025-40076?


## How do I fix CVE-2025-40076?

Apply the vendor's patch.

## Is CVE-2025-40076 being exploited?

There is no known exploitation of CVE-2025-40076 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40076 and fix it if it is affected.

What it is: CVE-2025-40076 is a vulnerability in Linux, published on 28 Oct 2025. 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-2025-40076 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-2025-40076/ (Markdown: https://insights.sbomify.com/CVE-2025-40076/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40076
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40076
- OSV: https://osv.dev/vulnerability/CVE-2025-40076

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40076/
Summaries are generated and may contain mistakes; the official description above is the record.