# CVE-2026-80816: ALSA: FCP: Use a private URB for the notification endpoint

> A null pointer dereference in the ALSA FCP driver causes a kernel crash when a specific USB audio device is connected.

- **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:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-80816, DEBIAN-CVE-2026-80816, GHSA-42j7-3823-x574, UBUNTU-CVE-2026-80816

## What is CVE-2026-80816?

CVE-2026-80816 is a vulnerability in Linux, published on 4 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:

ALSA: FCP: Use a private URB for the notification endpoint

fcp_init_notify() used mixer->urb, which snd_usb_mixer_status_create()
allocates for the optional UAC2 status interrupt endpoint and mixer.c
kills, resubmits and frees. On a device with that endpoint,
fcp_init_notify()'s "already set up" early return fires on the status
URB and returns success without doing anything. No FCP notification
URB is submitted, and cmd_done is left zeroed because it is
initialised past that early return and nowhere else. fcp_init() then
issues init1_opcode and wait_for_completion_timeout() would crash
adding to the zeroed wait.head. fcp_cleanup_urb() would also kill and
free mixer.c's status URB.

Use a separate URB in fcp_data, and initialise cmd_done in
fcp_init_private() where fcp_data is allocated. fcp_init_notify() is
reached again after suspend via fcp_reinit(), and the URB kill path in
fcp_notify() completes cmd_done, leaving a stale count that would
satisfy the next command's wait before the device ACKs. Use
reinit_completion() to clear it.

## Which versions are affected by CVE-2026-80816?


## How do I fix CVE-2026-80816?

Apply the vendor's patch.

## Is CVE-2026-80816 being exploited?

There is no known exploitation of CVE-2026-80816 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80816 and fix it if it is affected.

What it is: CVE-2026-80816 is a vulnerability in Linux, published on 4 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-2026-80816 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-2026-80816/ (Markdown: https://insights.sbomify.com/CVE-2026-80816/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80816
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80816
- OSV: https://osv.dev/vulnerability/CVE-2026-80816

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80816/
Summaries are generated and may contain mistakes; the official description above is the record.