nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12
has an ndb_queue_rq use-after-free that could be triggered by local
attackers (with access to the nbd device) via an I/O request at a certain
point during device setup, aka CID-b98e762e3d71.

It was discovered that the network block device (nbd) driver in the Linux
kernel contained a use-after-free vulnerability during device setup. A
local attacker with access to the nbd device could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.