# CVE-2024-26812: vfio/pci: Create persistent INTx handler

> A null pointer dereference in the Linux kernel VFIO PCI driver allows local attackers to cause a denial of service via specific interrupt handling sequences.

- **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:** 5 Apr 2024
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-58836, BELL-CVE-2024-26812, DEBIAN-CVE-2024-26812, GHSA-p8g6-7v7w-4whg, UBUNTU-CVE-2024-26812

## What is CVE-2024-26812?

CVE-2024-26812 is a high-severity vulnerability in Debian Debian Linux, published on 5 Apr 2024. 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:

vfio/pci: Create persistent INTx handler

A vulnerability exists where the eventfd for INTx signaling can be
deconfigured, which unregisters the IRQ handler but still allows
eventfds to be signaled with a NULL context through the SET_IRQS ioctl
or through unmask irqfd if the device interrupt is pending.

Ideally this could be solved with some additional locking; the igate
mutex serializes the ioctl and config space accesses, and the interrupt
handler is unregistered relative to the trigger, but the irqfd path
runs asynchronous to those.  The igate mutex cannot be acquired from the
atomic context of the eventfd wake function.  Disabling the irqfd
relative to the eventfd registration is potentially incompatible with
existing userspace.

As a result, the solution implemented here moves configuration of the
INTx interrupt handler to track the lifetime of the INTx context object
and irq_type configuration, rather than registration of a particular
trigger eventfd.  Synchronization is added between the ioctl path and
eventfd_signal() wrapper such that the eventfd trigger can be
dynamically updated relative to in-flight interrupts or irqfd callbacks.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-26812?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-26812?

Apply the vendor's patch.

## Is CVE-2024-26812 being exploited?

There is no known exploitation of CVE-2024-26812 in the wild and no public exploit code.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26812 and fix it if it is affected.

What it is: CVE-2024-26812 is a high-severity vulnerability in Debian Debian Linux, published on 5 Apr 2024. 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-2024-26812 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-26812/ (Markdown: https://insights.sbomify.com/CVE-2024-26812/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26812
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26812
- OSV: https://osv.dev/vulnerability/CVE-2024-26812

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26812/
Summaries are generated and may contain mistakes; the official description above is the record.