CVE-2026-98737
Bluetooth: hci_sync: Fix inquiry cache use-after-free
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.
INFO
Published Date :
Oct. 18, 2026, 4:17 p.m.
Last Modified :
Oct. 18, 2026, 4:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Hold hdev->lock across inquiry cache lookups.
- Copy remote address before unlocking.
- Release lock before sending synchronous HCI commands.
References to Advisories, Solutions, and Tools
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CVE-2026-98737.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-98737 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
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stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-98737
weaknesses.
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 18, 2026
Action Type Old Value New Value 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. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/98xxx/CVE-2026-98737.json">CVE-2026-98737</a> Added Reference https://git.kernel.org/stable/c/333257e6e4a7bcaaea82fd357121d0f1e6b76c7b Added Reference https://git.kernel.org/stable/c/52edf1c0e59dea37b8368c4a2559dca96b2fdfea Added Reference https://git.kernel.org/stable/c/8ed67535fdff40ca652bcd4ac7da68d11d01bd34 Added Reference https://git.kernel.org/stable/c/a642f498f0b08f2aa9f4a69468db92f57a72349d