--- id: CVE-2023-54164 title: 'Bluetooth: ISO: fix iso_conn related locking and validity issues' summary: |- In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix iso_conn related locking and validity issues sk->sk_state indicates whether iso_pi(sk)->conn is valid. Operations that check/update sk_state and ac… severity: high cvss: 8 cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: cna vendor: Linux product: Linux affected: - >- Linux >= c524f9561c657b8af26dd4f67092b8928261aa62 < e969bfed84c1f88dc722a678ee08488e86f0ec1a - >- Linux >= 241f51931c35085449502c10f64fb3ecd6e02171 < 88ad50f2b843a510bd7c922c0a4e2484aff9d645 - >- Linux >= 241f51931c35085449502c10f64fb3ecd6e02171 < d40ae85ee62e3666f45bc61864b22121346f88ef - Linux 2539cbc625c560d5432e2f0fc04bfe4a889cf737 - Linux >= 6.1.9 < 6.1.42 - Linux 6.2 ssvc: exploitation: none automatable: 'no' technicalImpact: total timestamp: '2026-10-15T21:38:48.372109Z' published: '2025-12-30' updated: '2026-10-15' sourceUpdated: '2026-10-15T21:41:40.592Z' source: CVEORG sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-54164' references: - url: 'https://git.kernel.org/stable/c/e969bfed84c1f88dc722a678ee08488e86f0ec1a' - url: 'https://git.kernel.org/stable/c/88ad50f2b843a510bd7c922c0a4e2484aff9d645' - url: 'https://git.kernel.org/stable/c/d40ae85ee62e3666f45bc61864b22121346f88ef' tags: - cve.org epss: 0.00284 epssPercentile: 0.19514 ingestedAt: '2026-10-15T22:48:25.431Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix iso_conn related locking and validity issues sk->sk_state indicates whether iso_pi(sk)->conn is valid. Operations that check/update sk_state and access conn should hold lock_sock, otherwise they can race. The order of taking locks is hci_dev_lock > lock_sock > iso_conn_lock, which is how it is in connect/disconnect_cfm -> iso_conn_del -> iso_chan_del. Fix locking in iso_connect_cis/bis and sendmsg/recvmsg to take lock_sock around updating sk_state and conn. iso_conn_del must not occur during iso_connect_cis/bis, as it frees the iso_conn. Hold hdev->lock longer to prevent that. This should not reintroduce the issue fixed in commit 241f51931c35 ("Bluetooth: ISO: Avoid circular locking dependency"), since the we acquire locks in order. We retain the fix in iso_sock_connect to release lock_sock before iso_connect_* acquires hdev->lock. Similarly for commit 6a5ad251b7cd ("Bluetooth: ISO: Fix possible circular locking dependency"). We retain the fix in iso_conn_ready to not acquire iso_conn_lock before lock_sock. iso_conn_add shall return iso_conn with valid hcon. Make it so also when reusing an old CIS connection waiting for disconnect timeout (see __iso_sock_close where conn->hcon is set to NULL). Trace with iso_conn_del after iso_chan_add in iso_connect_cis: =============================================================== iso_sock_create:771: sock 00000000be9b69b7 iso_sock_init:693: sk 000000004dff667e iso_sock_bind:827: sk 000000004dff667e 70:1a:b8:98:ff:a2 type 1 iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_setsockopt:1289: sk 000000004dff667e iso_sock_connect:875: sk 000000004dff667e iso_connect_cis:353: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da hci_get_route:1199: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da hci_conn_add:1005: hci0 dst 28:3d:c2:4a:7e:da iso_conn_add:140: hcon 000000007b65d182 conn 00000000daf8625e __iso_chan_add:214: conn 00000000daf8625e iso_connect_cfm:1700: hcon 000000007b65d182 bdaddr 28:3d:c2:4a:7e:da status 12 iso_conn_del:187: hcon 000000007b65d182 conn 00000000daf8625e, err 16 iso_sock_clear_timer:117: sock 000000004dff667e state 3 iso_chan_del:153: sk 000000004dff667e, conn 00000000daf8625e, err 16 hci_conn_del:1151: hci0 hcon 000000007b65d182 handle 65535 hci_conn_unlink:1102: hci0: hcon 000000007b65d182 hci_chan_list_flush:2780: hcon 000000007b65d182 iso_sock_getsockopt:1376: sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getsockopt:1376: sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_getname:1070: sock 00000000be9b69b7, sk 000000004dff667e iso_sock_shutdown:1434: sock 00000000be9b69b7, sk 000000004dff667e, how 1 __iso_sock_close:632: sk 000000004dff667e state 5 socket 00000000be9b69b7 BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 8000000006467067 P4D 8000000006467067 PUD 3f5f067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 RIP: 0010:__iso_sock_close (net/bluetooth/iso.c:664) bluetooth =============================================================== Trace with iso_conn_del before iso_chan_add in iso_connect_cis: =============================================================== iso_connect_cis:356: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da ... iso_conn_add:140: hcon 0000000093bc551f conn 00000000768ae504 hci_dev_put:1487: hci0 orig refcnt 21 hci_event_packet:7607: hci0: e ---truncated--- ## Affected - `Linux >= c524f9561c657b8af26dd4f67092b8928261aa62 < e969bfed84c1f88dc722a678ee08488e86f0ec1a` - `Linux >= 241f51931c35085449502c10f64fb3ecd6e02171 < 88ad50f2b843a510bd7c922c0a4e2484aff9d645` - `Linux >= 241f51931c35085449502c10f64fb3ecd6e02171 < d40ae85ee62e3666f45bc61864b22121346f88ef` - `Linux 2539cbc625c560d5432e2f0fc04bfe4a889cf737` - `Linux >= 6.1.9 < 6.1.42` - `Linux 6.2` ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges.