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CVE-2026-93247

Bluetooth: mgmt: fix 'hdev->discovery.uuids' NULL dereference PUBLISHED

Description (CNA)

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 ]---

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 86f3dcd1f331cfd4fd7ec88906955134ec51afbe before f02c01ccd12cb2b8a290077d4c90f29a6e109b16; affected 7ce9bb0b95fc280e9212b8922590c492ca1d9c39 before bbd262d2d750b67b15a5e1008d3848309c87e7a7; affected 16852eccbdfaf41a666705e3f8be55cf2864c5ca before 18fda026a13c5abd6c1e0dfd3549f490b73378fb; affected 2935e556850e9c94d7a00adf14d3cd7fe406ac03 before c3f63610bceaa182e4683b23cc47baf36b5f1496; affected 2935e556850e9c94d7a00adf14d3cd7fe406ac03 before ee2135a14fb2a3e176149122764d293f0796b1eb; affected 2935e556850e9c94d7a00adf14d3cd7fe406ac03 before 59eecbe2f2f38d8f3e1104bd11da97f9a2c58998; affected a351ff6b8ecca4229afaa0d98042bead8de64799; affected f8069f34c4c976786ded97498012225af87435d7; affected 6.1.159 before 6.1.188; affected 6.6.117 before 6.6.157; affected 6.12.42 before 6.12.110; affected 6.15.10 before 6.16; affected 6.16.1 before 6.17
Linux / Linuxaffected 6.17; unaffected 0 before 6.17; unaffected 6.1.188 through 6.1.*; unaffected 6.6.157 through 6.6.*; unaffected 6.12.110 through 6.12.*; unaffected 6.18.52 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References