In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan
For L2CAP sockets without owning sk->sk_socket, reading
l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() ->
l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks,
but access in l2cap_sock_cleanup_listen() has unsafe lockless read.
[Task 1] [Task 2 (hdev->workqueue)]
l2cap_sock_release(parent) l2cap_disconn_cfm
l2cap_sock_cleanup_listen l2cap_conn_del
bt_accept_dequeue l2cap_chan_del
lock_sock(sk) l2cap_sock_teardown_cb
bt_accept_unlink
bt_sk(sk)->parent = NULL
release_sock(sk) ----------------> lock_sock(sk)
parent = /* NULL */
lock_sock(sk) <--------------------- release_sock(sk)
sock_set_flag(sk, SOCK_ZAPPED)
l2cap_sock_close_cb
l2cap_sock_kill(sk)
l2cap_sock_put_chan
chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL
l2cap_chan_hold_unless_zero l2cap_put_chan(chan)
kref_get_unless_zero(&chan->ref)
Task 1 may observe NULL which causes null-ptr-deref.
Fix the race by taking lock_sock() in l2cap_sock_kill() to
synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not
needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL.
Clarify code comments vs. locking.
Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan
For L2CAP sockets without owning sk->sk_socket, reading
l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() ->
l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks,
but access in l2cap_sock_cleanup_listen() has unsafe lockless read.
[Task 1] [Task 2 (hdev->workqueue)]
l2cap_sock_release(parent) l2cap_disconn_cfm
l2cap_sock_cleanup_listen l2cap_conn_del
bt_accept_dequeue l2cap_chan_del
lock_sock(sk) l2cap_sock_teardown_cb
bt_accept_unlink
bt_sk(sk)->parent = NULL
release_sock(sk) ----------------> lock_sock(sk)
parent = /* NULL */
lock_sock(sk) <--------------------- release_sock(sk)
sock_set_flag(sk, SOCK_ZAPPED)
l2cap_sock_close_cb
l2cap_sock_kill(sk)
l2cap_sock_put_chan
chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL
l2cap_chan_hold_unless_zero l2cap_put_chan(chan)
kref_get_unless_zero(&chan->ref)
Task 1 may observe NULL which causes null-ptr-deref.
Fix the race by taking lock_sock() in l2cap_sock_kill() to
synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not
needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL.
Clarify code comments vs. locking.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan For L2CAP sockets without owning sk->sk_socket, reading l2cap_pi(sk)->chan may race against concurrent l2cap_sock_kill() -> l2cap_sock_put_chan(). This excludes simultaneous proto_ops callbacks, but access in l2cap_sock_cleanup_listen() has unsafe lockless read. [Task 1] [Task 2 (hdev->workqueue)] l2cap_sock_release(parent) l2cap_disconn_cfm l2cap_sock_cleanup_listen l2cap_conn_del bt_accept_dequeue l2cap_chan_del lock_sock(sk) l2cap_sock_teardown_cb bt_accept_unlink bt_sk(sk)->parent = NULL release_sock(sk) ----------------> lock_sock(sk) parent = /* NULL */ lock_sock(sk) <--------------------- release_sock(sk) sock_set_flag(sk, SOCK_ZAPPED) l2cap_sock_close_cb l2cap_sock_kill(sk) l2cap_sock_put_chan chan = READ l2cap_pi(sk)->chan l2cap_pi(sk)->chan = NULL l2cap_chan_hold_unless_zero l2cap_put_chan(chan) kref_get_unless_zero(&chan->ref) Task 1 may observe NULL which causes null-ptr-deref. Fix the race by taking lock_sock() in l2cap_sock_kill() to synchronize with l2cap_sock_cleanup_listen(). hold_unless_zero() is not needed here, l2cap_pi(sk)->chan owns reference if it is non-NULL. Clarify code comments vs. locking. | |
| Title | Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:06:05.478Z
Reserved: 2026-09-11T19:38:34.786Z
Link: CVE-2026-90091
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:00.563
Modified: 2026-09-17T17:17:00.563
Link: CVE-2026-90091
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.