In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER

When protocol sets HCI_PROTO_DEFER, hci_conn_request_evt() calls
hci_connect_cfm(conn) without hdev->lock. Generally hci_connect_cfm()
assumes it is held, and if conn is deleted concurrently -> UAF.

Only SCO and ISO set HCI_PROTO_DEFER and only for defer setup listen,
and HCI_EV_CONN_REQUEST is not generated for ISO.  In the non-deferred
listening socket code paths, hci_connect_cfm(conn) is called with
hdev->lock held.

Fix by holding the lock.

https://git.kernel.org/stable/c/385b2d0468a0871fc716c549fa3b0c257c7dbcb3

https://git.kernel.org/stable/c/541d5bf9b5afaf41090b2a3aa7b47f2db2ff801f

https://git.kernel.org/stable/c/5c7209a341ff2ac338b2b0375c34a307b37c9ac2

https://git.kernel.org/stable/c/60e3f4ff02d1f2d55bfbf2ca32a97285a9771ee4

https://git.kernel.org/stable/c/6b4d226d01ab7da0d2027a2a1e3a6079152e5065

https://git.kernel.org/stable/c/9d4a6c0f43fc5e4d4f062e8e450e5483eb74176e

https://git.kernel.org/stable/c/c27224daf0b08efbb2b24ed64b6139b294f5473a

https://git.kernel.org/stable/c/c7777f534a8018ae4bb1c80d8925af4df588a314

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