Description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: Serialize SCO and ISO scheduling with teardown
hci_low_sent() selects a connection under RCU but drops the read lock
before calculating its quota and returning it to the scheduler. The
connection is then used without lifetime protection by hci_sched_iso()
and hci_sched_sco().
After the TX worker drops the RCU read lock, hci_abort_conn_sync() on
hdev->req_workqueue can remove the connection from the hash, complete
synchronize_rcu(), purge its queues and release it. The TX worker on
hdev->workqueue can then access the freed connection in hci_quote_sent()
or while dequeuing packets and updating conn->sent.
KASAN reported:
BUG: KASAN: slab-use-after-free in hci_low_sent+0x730/0x840
Workqueue: hci0 hci_tx_work
Call Trace:
hci_low_sent+0x730/0x840
hci_sched_iso+0x25e/0x4d0
hci_tx_work+0x239/0xcb0
Allocated by task 93:
__hci_conn_add+0x16f/0x1b40
hci_bind_bis+0x782/0x17b0
hci_connect_bis+0xa0/0x510
iso_sock_connect+0x589/0x1050
Freed by task 88:
kfree+0x131/0x3c0
device_release+0xc8/0x240
kobject_put+0x14d/0x280
hci_conn_del+0x55a/0xe80
hci_disconnect_sync+0x156/0x180
hci_abort_conn_sync+0x3e7/0x940
hci_cmd_sync_work+0x13c/0x290
Hold hci_dev_lock() across connection selection and transmission in both
SCO and ISO scheduling, serializing them with connection teardown. This
also prevents queuing completion timestamps after the connection queues
have been purged. Extending RCU across transmission would be unsafe
because the transmit path can sleep. Keep the ISO timeout check outside
the mutex since hci_link_tx_to() takes it itself.
The preceding channel fix already holds this mutex in the ACL and LE
schedulers, which call the SCO scheduler between packets. Move the SCO
body to __hci_sched_sco(), assert that its caller holds the mutex, and
use it directly from these locked paths. Keep a locking hci_sched_sco()
wrapper for the direct calls from hci_tx_work(). This avoids recursively
acquiring the device mutex while preserving the scheduling order.
Remove the obsolete claim that connection removal disables TX.
Bluetooth: hci_core: Serialize SCO and ISO scheduling with teardown
hci_low_sent() selects a connection under RCU but drops the read lock
before calculating its quota and returning it to the scheduler. The
connection is then used without lifetime protection by hci_sched_iso()
and hci_sched_sco().
After the TX worker drops the RCU read lock, hci_abort_conn_sync() on
hdev->req_workqueue can remove the connection from the hash, complete
synchronize_rcu(), purge its queues and release it. The TX worker on
hdev->workqueue can then access the freed connection in hci_quote_sent()
or while dequeuing packets and updating conn->sent.
KASAN reported:
BUG: KASAN: slab-use-after-free in hci_low_sent+0x730/0x840
Workqueue: hci0 hci_tx_work
Call Trace:
hci_low_sent+0x730/0x840
hci_sched_iso+0x25e/0x4d0
hci_tx_work+0x239/0xcb0
Allocated by task 93:
__hci_conn_add+0x16f/0x1b40
hci_bind_bis+0x782/0x17b0
hci_connect_bis+0xa0/0x510
iso_sock_connect+0x589/0x1050
Freed by task 88:
kfree+0x131/0x3c0
device_release+0xc8/0x240
kobject_put+0x14d/0x280
hci_conn_del+0x55a/0xe80
hci_disconnect_sync+0x156/0x180
hci_abort_conn_sync+0x3e7/0x940
hci_cmd_sync_work+0x13c/0x290
Hold hci_dev_lock() across connection selection and transmission in both
SCO and ISO scheduling, serializing them with connection teardown. This
also prevents queuing completion timestamps after the connection queues
have been purged. Extending RCU across transmission would be unsafe
because the transmit path can sleep. Keep the ISO timeout check outside
the mutex since hci_link_tx_to() takes it itself.
The preceding channel fix already holds this mutex in the ACL and LE
schedulers, which call the SCO scheduler between packets. Move the SCO
body to __hci_sched_sco(), assert that its caller holds the mutex, and
use it directly from these locked paths. Keep a locking hci_sched_sco()
wrapper for the direct calls from hci_tx_work(). This avoids recursively
acquiring the device mutex while preserving the scheduling order.
Remove the obsolete claim that connection removal disables TX.
Published:
2026-10-18
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
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 |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Advisories
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References
History
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Serialize SCO and ISO scheduling with teardown hci_low_sent() selects a connection under RCU but drops the read lock before calculating its quota and returning it to the scheduler. The connection is then used without lifetime protection by hci_sched_iso() and hci_sched_sco(). After the TX worker drops the RCU read lock, hci_abort_conn_sync() on hdev->req_workqueue can remove the connection from the hash, complete synchronize_rcu(), purge its queues and release it. The TX worker on hdev->workqueue can then access the freed connection in hci_quote_sent() or while dequeuing packets and updating conn->sent. KASAN reported: BUG: KASAN: slab-use-after-free in hci_low_sent+0x730/0x840 Workqueue: hci0 hci_tx_work Call Trace: hci_low_sent+0x730/0x840 hci_sched_iso+0x25e/0x4d0 hci_tx_work+0x239/0xcb0 Allocated by task 93: __hci_conn_add+0x16f/0x1b40 hci_bind_bis+0x782/0x17b0 hci_connect_bis+0xa0/0x510 iso_sock_connect+0x589/0x1050 Freed by task 88: kfree+0x131/0x3c0 device_release+0xc8/0x240 kobject_put+0x14d/0x280 hci_conn_del+0x55a/0xe80 hci_disconnect_sync+0x156/0x180 hci_abort_conn_sync+0x3e7/0x940 hci_cmd_sync_work+0x13c/0x290 Hold hci_dev_lock() across connection selection and transmission in both SCO and ISO scheduling, serializing them with connection teardown. This also prevents queuing completion timestamps after the connection queues have been purged. Extending RCU across transmission would be unsafe because the transmit path can sleep. Keep the ISO timeout check outside the mutex since hci_link_tx_to() takes it itself. The preceding channel fix already holds this mutex in the ACL and LE schedulers, which call the SCO scheduler between packets. Move the SCO body to __hci_sched_sco(), assert that its caller holds the mutex, and use it directly from these locked paths. Keep a locking hci_sched_sco() wrapper for the direct calls from hci_tx_work(). This avoids recursively acquiring the device mutex while preserving the scheduling order. Remove the obsolete claim that connection removal disables TX. | |
| Title | Bluetooth: hci_core: Serialize SCO and ISO scheduling with teardown | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:47:12.203Z
Reserved: 2026-09-25T10:25:14.367Z
Link: CVE-2026-98734
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:27.010
Modified: 2026-10-18T16:17:27.010
Link: CVE-2026-98734
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.