# CVE-2021-47424: i40e: Fix freeing of uninitialized misc IRQ vector

> A flaw in the i40e network driver causes a kernel Oops when freeing uninitialized IRQ vectors during failed probe, leading to denial of service.

- **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:** 21 May 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-47424, GHSA-hf7w-m8fc-q8fp, UBUNTU-CVE-2021-47424

## What is CVE-2021-47424?

CVE-2021-47424 is a medium-severity vulnerability in Linux kernel, published on 21 May 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:

i40e: Fix freeing of uninitialized misc IRQ vector

When VSI set up failed in i40e_probe() as part of PF switch set up
driver was trying to free misc IRQ vectors in
i40e_clear_interrupt_scheme and produced a kernel Oops:

   Trying to free already-free IRQ 266
   WARNING: CPU: 0 PID: 5 at kernel/irq/manage.c:1731 __free_irq+0x9a/0x300
   Workqueue: events work_for_cpu_fn
   RIP: 0010:__free_irq+0x9a/0x300
   Call Trace:
   ? synchronize_irq+0x3a/0xa0
   free_irq+0x2e/0x60
   i40e_clear_interrupt_scheme+0x53/0x190 [i40e]
   i40e_probe.part.108+0x134b/0x1a40 [i40e]
   ? kmem_cache_alloc+0x158/0x1c0
   ? acpi_ut_update_ref_count.part.1+0x8e/0x345
   ? acpi_ut_update_object_reference+0x15e/0x1e2
   ? strstr+0x21/0x70
   ? irq_get_irq_data+0xa/0x20
   ? mp_check_pin_attr+0x13/0xc0
   ? irq_get_irq_data+0xa/0x20
   ? mp_map_pin_to_irq+0xd3/0x2f0
   ? acpi_register_gsi_ioapic+0x93/0x170
   ? pci_conf1_read+0xa4/0x100
   ? pci_bus_read_config_word+0x49/0x70
   ? do_pci_enable_device+0xcc/0x100
   local_pci_probe+0x41/0x90
   work_for_cpu_fn+0x16/0x20
   process_one_work+0x1a7/0x360
   worker_thread+0x1cf/0x390
   ? create_worker+0x1a0/0x1a0
   kthread+0x112/0x130
   ? kthread_flush_work_fn+0x10/0x10
   ret_from_fork+0x1f/0x40

The problem is that at that point misc IRQ vectors
were not allocated yet and we get a call trace
that driver is trying to free already free IRQ vectors.

Add a check in i40e_clear_interrupt_scheme for __I40E_MISC_IRQ_REQUESTED
PF state before calling i40e_free_misc_vector. This state is set only if
misc IRQ vectors were properly initialized.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2021-47424?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47424?

Apply the vendor's patch.

## Is CVE-2021-47424 being exploited?

There is no known exploitation of CVE-2021-47424 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-2021-47424 and fix it if it is affected.

What it is: CVE-2021-47424 is a medium-severity vulnerability in Linux kernel, published on 21 May 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-2021-47424 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-2021-47424/ (Markdown: https://insights.sbomify.com/CVE-2021-47424/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47424
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47424
- OSV: https://osv.dev/vulnerability/CVE-2021-47424

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47424/
Summaries are generated and may contain mistakes; the official description above is the record.