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. CREATE(Triage):(User=admin) CVE-2021-3348 (https://nvd.nist.gov/vuln/detail/CVE-2021-3348)