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
<Note: sk_state is BT_BOUND (3), so iso_connect_cis is still
running at this point>
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
<Note: sk_state is BT_CONNECT (5), even though iso_chan_del sets
BT_CLOSED (6). Only iso_connect_cis sets it to BT_CONNECT, so it
must be that iso_chan_del occurred between iso_chan_add and end of
iso_connect_cis.>
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---

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00024.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
c524f9561c657b8af26dd4f67092b8928261aa62 affected < e969bfed84c1f88dc722a678ee08488e86f0ec1a
241f51931c35085449502c10f64fb3ecd6e02171 affected < 88ad50f2b843a510bd7c922c0a4e2484aff9d645
241f51931c35085449502c10f64fb3ecd6e02171 affected < d40ae85ee62e3666f45bc61864b22121346f88ef
2539cbc625c560d5432e2f0fc04bfe4a889cf737 affected —
Linux Linux affected
Version Status Constraints
6.2 affected —
0 unaffected < 6.2
6.1.42 unaffected ≤ 6.1.*
6.4.7 unaffected ≤ 6.4.*
6.5 unaffected ≤ *

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References
Link Providers
https://git.kernel.org/stable/c/88ad50f2b843a510bd7c922c0a4e2484aff9d645 cve-icon cve-icon
https://git.kernel.org/stable/c/d40ae85ee62e3666f45bc61864b22121346f88ef cve-icon cve-icon
https://git.kernel.org/stable/c/e969bfed84c1f88dc722a678ee08488e86f0ec1a cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025123018-CVE-2023-54164-9a2a@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2023-54164 cve-icon
https://www.cve.org/CVERecord?id=CVE-2023-54164 cve-icon
History

Wed, 31 Dec 2025 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important

Tue, 30 Dec 2025 12:30:00 +0000

Type Values Removed Values Added
Description 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 <Note: sk_state is BT_BOUND (3), so iso_connect_cis is still running at this point> 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 <Note: sk_state is BT_CONNECT (5), even though iso_chan_del sets BT_CLOSED (6). Only iso_connect_cis sets it to BT_CONNECT, so it must be that iso_chan_del occurred between iso_chan_add and end of iso_connect_cis.> 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---
Title Bluetooth: ISO: fix iso_conn related locking and validity issues
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-12-30T12:08:40.357Z

Reserved: 2025-12-30T12:06:44.495Z

Link: CVE-2023-54164

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-12-30T13:16:04.167

Modified: 2025-12-31T20:43:05.160

Link: CVE-2023-54164

cve-icon Redhat

Severity : Important

Publid Date: 2025-12-30T00:00:00Z

Links: CVE-2023-54164 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.