In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: Fix inquiry cache use-after-free
The sync command worker holds hdev->req_lock, but inquiry-cache updates
and flushes use hdev->lock. Both hci_acl_create_conn_sync() and
hci_stop_discovery_sync() look up entries and read their fields without
taking hdev->lock.
After either lookup returns, a concurrent HCIINQUIRY ioctl can acquire
hdev->lock and flush the cache, freeing the entry. The worker then reads
the freed entry while preparing a create-connection or remote-name-cancel
command. The list traversal also races with cache updates and removal.
KASAN reported these accesses:
BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5f1/0x650
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
hci_acl_create_conn_sync+0x5f1/0x650
hci_cmd_sync_work+0x13c/0x290
Allocated by task 90:
hci_inquiry_cache_update+0x3e6/0x7d0
hci_inquiry_result_evt+0x3cb/0x560
Freed by task 93:
hci_inquiry_cache_flush+0x111/0x2b0
hci_inquiry+0x2f2/0x780
hci_sock_ioctl+0x269/0x5f0
BUG: KASAN: slab-use-after-free in hci_stop_discovery_sync+0x3b1/0x3c0
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
hci_stop_discovery_sync+0x3b1/0x3c0
hci_cmd_sync_work+0x173/0x300
Allocated by task 86:
hci_inquiry_cache_update+0x483/0x940
hci_inquiry_result_evt+0x3cb/0x560
Freed by task 91:
hci_inquiry_cache_flush+0x13e/0x2f0
hci_inquiry+0x2f2/0x780
hci_sock_ioctl+0x269/0x5f0
Hold hdev->lock across each lookup and all reads from its result. Copy the
remote address before unlocking so discovery cancellation does not retain
a cache entry pointer. Release the lock before sending synchronous HCI
commands, since their completion handlers may need the same lock.
Bluetooth: hci_sync: Fix inquiry cache use-after-free
The sync command worker holds hdev->req_lock, but inquiry-cache updates
and flushes use hdev->lock. Both hci_acl_create_conn_sync() and
hci_stop_discovery_sync() look up entries and read their fields without
taking hdev->lock.
After either lookup returns, a concurrent HCIINQUIRY ioctl can acquire
hdev->lock and flush the cache, freeing the entry. The worker then reads
the freed entry while preparing a create-connection or remote-name-cancel
command. The list traversal also races with cache updates and removal.
KASAN reported these accesses:
BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5f1/0x650
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
hci_acl_create_conn_sync+0x5f1/0x650
hci_cmd_sync_work+0x13c/0x290
Allocated by task 90:
hci_inquiry_cache_update+0x3e6/0x7d0
hci_inquiry_result_evt+0x3cb/0x560
Freed by task 93:
hci_inquiry_cache_flush+0x111/0x2b0
hci_inquiry+0x2f2/0x780
hci_sock_ioctl+0x269/0x5f0
BUG: KASAN: slab-use-after-free in hci_stop_discovery_sync+0x3b1/0x3c0
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
hci_stop_discovery_sync+0x3b1/0x3c0
hci_cmd_sync_work+0x173/0x300
Allocated by task 86:
hci_inquiry_cache_update+0x483/0x940
hci_inquiry_result_evt+0x3cb/0x560
Freed by task 91:
hci_inquiry_cache_flush+0x13e/0x2f0
hci_inquiry+0x2f2/0x780
hci_sock_ioctl+0x269/0x5f0
Hold hdev->lock across each lookup and all reads from its result. Copy the
remote address before unlocking so discovery cancellation does not retain
a cache entry pointer. Release the lock before sending synchronous HCI
commands, since their completion handlers may need the same lock.
Metrics
Affected Vendors & Products
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Fixes
Solution
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Workaround
No workaround given by the vendor.
References
History
Sun, 18 Oct 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-416 |
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_sync: Fix inquiry cache use-after-free The sync command worker holds hdev->req_lock, but inquiry-cache updates and flushes use hdev->lock. Both hci_acl_create_conn_sync() and hci_stop_discovery_sync() look up entries and read their fields without taking hdev->lock. After either lookup returns, a concurrent HCIINQUIRY ioctl can acquire hdev->lock and flush the cache, freeing the entry. The worker then reads the freed entry while preparing a create-connection or remote-name-cancel command. The list traversal also races with cache updates and removal. KASAN reported these accesses: BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5f1/0x650 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_acl_create_conn_sync+0x5f1/0x650 hci_cmd_sync_work+0x13c/0x290 Allocated by task 90: hci_inquiry_cache_update+0x3e6/0x7d0 hci_inquiry_result_evt+0x3cb/0x560 Freed by task 93: hci_inquiry_cache_flush+0x111/0x2b0 hci_inquiry+0x2f2/0x780 hci_sock_ioctl+0x269/0x5f0 BUG: KASAN: slab-use-after-free in hci_stop_discovery_sync+0x3b1/0x3c0 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_stop_discovery_sync+0x3b1/0x3c0 hci_cmd_sync_work+0x173/0x300 Allocated by task 86: hci_inquiry_cache_update+0x483/0x940 hci_inquiry_result_evt+0x3cb/0x560 Freed by task 91: hci_inquiry_cache_flush+0x13e/0x2f0 hci_inquiry+0x2f2/0x780 hci_sock_ioctl+0x269/0x5f0 Hold hdev->lock across each lookup and all reads from its result. Copy the remote address before unlocking so discovery cancellation does not retain a cache entry pointer. Release the lock before sending synchronous HCI commands, since their completion handlers may need the same lock. | |
| Title | Bluetooth: hci_sync: Fix inquiry cache use-after-free | |
| 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: 2026-10-18T15:47:14.936Z
Reserved: 2026-09-25T10:25:14.367Z
Link: CVE-2026-98737
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:27.370
Modified: 2026-10-18T16:17:27.370
Link: CVE-2026-98737
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-10-18T20:15:14Z
Weaknesses