In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference
'uuid_count' member of struct 'discovery_state' is assigned and read
without any locks, so there is a chance of situation when
uuid_count != 0, but uuids is NULL and there will be NULL pointer
dereference.
Possible race:
'hci_update_passive_scan_sync'
'hci_discovery_filter_clear'
hdev->discovery.uuid_count = 0;
<----------------------preempted----------------------------->
'start_service_discovery'
// Set uuid_count to value != 0
hdev->discovery.uuid_count = uuid_count;
hdev->discovery.uuids = kmemdup(...);
<----------------------preempted----------------------------->
spin_lock(&hdev->discovery.lock);
kfree(hdev->discovery.uuids);
hdev->discovery.uuids = NULL;
spin_unlock(&hdev->discovery.lock);
Now uuids == NULL and uuid_count != 0.
So 'mgmt_device_found' -> 'is_filter_match' -> 'eir_has_uuids' receives
non consistent discovery state, where NULL dereference of uuids happens.
To fix it let's add discovery.lock around every read/write of uuid_count,
uuids pair of struct members. It is also important to assign uuid_count
value only after success kmemdup() allocation in
start_service_discovery(), otherwise uuids is NULL, because kmemdup failed,
but uuid_count is already assigned to non zero value.
The following panic happens:
[ ] ------------[ cut here ]------------
[ ] Unable to handle kernel NULL pointer dereference at virtual
address 0000000000000000
[ ] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
[ ] CPU: 0 PID: 15056 Comm: kworker/u9:2
[ ] Workqueue: hci0 hci_rx_work
[ ] pstate: 10400009 (nzcV daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ ] pc : eir_has_uuids+0x2d8/0x590
[ ] lr : is_filter_match+0x258/0x320
...
[ ] Call trace:
[ ] eir_has_uuids+0x2d8/0x590
[ ] is_filter_match+0x258/0x320
[ ] mgmt_device_found+0x5b0/0xafc
[ ] process_adv_report.part.0+0x8c8/0xf14
[ ] hci_le_adv_report_evt+0x338/0x3f0
[ ] hci_le_meta_evt+0x1f0/0x4c8
[ ] hci_event_packet+0x440/0xc9c
[ ] hci_rx_work+0x44c/0xaf8
[ ] process_one_work+0x54c/0x103c
[ ] worker_thread+0x6c4/0x10c4
[ ] kthread+0x274/0x2ec
[ ] ret_from_fork+0x10/0x20
[ ] Code: 14000004 91004021 eb14003f 54000180 (f9400024)
[ ] ---[ end trace 0000000000000000 ]---
Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference
'uuid_count' member of struct 'discovery_state' is assigned and read
without any locks, so there is a chance of situation when
uuid_count != 0, but uuids is NULL and there will be NULL pointer
dereference.
Possible race:
'hci_update_passive_scan_sync'
'hci_discovery_filter_clear'
hdev->discovery.uuid_count = 0;
<----------------------preempted----------------------------->
'start_service_discovery'
// Set uuid_count to value != 0
hdev->discovery.uuid_count = uuid_count;
hdev->discovery.uuids = kmemdup(...);
<----------------------preempted----------------------------->
spin_lock(&hdev->discovery.lock);
kfree(hdev->discovery.uuids);
hdev->discovery.uuids = NULL;
spin_unlock(&hdev->discovery.lock);
Now uuids == NULL and uuid_count != 0.
So 'mgmt_device_found' -> 'is_filter_match' -> 'eir_has_uuids' receives
non consistent discovery state, where NULL dereference of uuids happens.
To fix it let's add discovery.lock around every read/write of uuid_count,
uuids pair of struct members. It is also important to assign uuid_count
value only after success kmemdup() allocation in
start_service_discovery(), otherwise uuids is NULL, because kmemdup failed,
but uuid_count is already assigned to non zero value.
The following panic happens:
[ ] ------------[ cut here ]------------
[ ] Unable to handle kernel NULL pointer dereference at virtual
address 0000000000000000
[ ] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
[ ] CPU: 0 PID: 15056 Comm: kworker/u9:2
[ ] Workqueue: hci0 hci_rx_work
[ ] pstate: 10400009 (nzcV daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ ] pc : eir_has_uuids+0x2d8/0x590
[ ] lr : is_filter_match+0x258/0x320
...
[ ] Call trace:
[ ] eir_has_uuids+0x2d8/0x590
[ ] is_filter_match+0x258/0x320
[ ] mgmt_device_found+0x5b0/0xafc
[ ] process_adv_report.part.0+0x8c8/0xf14
[ ] hci_le_adv_report_evt+0x338/0x3f0
[ ] hci_le_meta_evt+0x1f0/0x4c8
[ ] hci_event_packet+0x440/0xc9c
[ ] hci_rx_work+0x44c/0xaf8
[ ] process_one_work+0x54c/0x103c
[ ] worker_thread+0x6c4/0x10c4
[ ] kthread+0x274/0x2ec
[ ] ret_from_fork+0x10/0x20
[ ] Code: 14000004 91004021 eb14003f 54000180 (f9400024)
[ ] ---[ end trace 0000000000000000 ]---
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Affected Vendors & Products
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Fixes
Solution
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Workaround
No workaround given by the vendor.
References
History
Thu, 24 Sep 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference 'uuid_count' member of struct 'discovery_state' is assigned and read without any locks, so there is a chance of situation when uuid_count != 0, but uuids is NULL and there will be NULL pointer dereference. Possible race: 'hci_update_passive_scan_sync' 'hci_discovery_filter_clear' hdev->discovery.uuid_count = 0; <----------------------preempted-----------------------------> 'start_service_discovery' // Set uuid_count to value != 0 hdev->discovery.uuid_count = uuid_count; hdev->discovery.uuids = kmemdup(...); <----------------------preempted-----------------------------> spin_lock(&hdev->discovery.lock); kfree(hdev->discovery.uuids); hdev->discovery.uuids = NULL; spin_unlock(&hdev->discovery.lock); Now uuids == NULL and uuid_count != 0. So 'mgmt_device_found' -> 'is_filter_match' -> 'eir_has_uuids' receives non consistent discovery state, where NULL dereference of uuids happens. To fix it let's add discovery.lock around every read/write of uuid_count, uuids pair of struct members. It is also important to assign uuid_count value only after success kmemdup() allocation in start_service_discovery(), otherwise uuids is NULL, because kmemdup failed, but uuid_count is already assigned to non zero value. The following panic happens: [ ] ------------[ cut here ]------------ [ ] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ ] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP [ ] CPU: 0 PID: 15056 Comm: kworker/u9:2 [ ] Workqueue: hci0 hci_rx_work [ ] pstate: 10400009 (nzcV daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ ] pc : eir_has_uuids+0x2d8/0x590 [ ] lr : is_filter_match+0x258/0x320 ... [ ] Call trace: [ ] eir_has_uuids+0x2d8/0x590 [ ] is_filter_match+0x258/0x320 [ ] mgmt_device_found+0x5b0/0xafc [ ] process_adv_report.part.0+0x8c8/0xf14 [ ] hci_le_adv_report_evt+0x338/0x3f0 [ ] hci_le_meta_evt+0x1f0/0x4c8 [ ] hci_event_packet+0x440/0xc9c [ ] hci_rx_work+0x44c/0xaf8 [ ] process_one_work+0x54c/0x103c [ ] worker_thread+0x6c4/0x10c4 [ ] kthread+0x274/0x2ec [ ] ret_from_fork+0x10/0x20 [ ] Code: 14000004 91004021 eb14003f 54000180 (f9400024) [ ] ---[ end trace 0000000000000000 ]--- | |
| Title | Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference | |
| 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: 2026-09-24T15:51:04.897Z
Reserved: 2026-09-17T16:02:15.096Z
Link: CVE-2026-93247
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-24T16:17:20.803
Modified: 2026-09-24T16:17:20.803
Link: CVE-2026-93247
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.