A use-after-free in function hci_sock_bound_ioctl() of the Linux kernel HCI
subsystem was found in the way user calls ioct HCIUNBLOCKADDR or other way
triggers race condition of the call hci_unregister_dev() together with one
of the calls hci_sock_blacklist_add(), hci_sock_blacklist_del(),
hci_get_conn_info(), hci_get_auth_info(). A privileged local user could use
this flaw to crash the system or escalate their privileges on the system.
This flaw affects the Linux kernel versions prior to 5.13-rc5.

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle HCI device detach events, leading to a use-after-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code.