CVE-2026-80816

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.