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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Sources
Also known as BELL-CVE-2026-80816, DEBIAN-CVE-2026-80816, GHSA-42j7-3823-x574, UBUNTU-CVE-2026-80816.