GHSA-V2QR-F43F-H5VH

Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-09-24 18:31
VLAI
Details

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 ]---

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93247"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-24T16:17:20Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: mgmt: fix \u0027hdev-\u003ediscovery.uuids\u0027 NULL dereference\n\n\u0027uuid_count\u0027 member of struct \u0027discovery_state\u0027 is assigned and read\nwithout any locks, so there is a chance of situation when\nuuid_count != 0, but uuids is NULL and there will be NULL pointer\ndereference.\n\nPossible race:\n\u0027hci_update_passive_scan_sync\u0027\n  \u0027hci_discovery_filter_clear\u0027\n    hdev-\u003ediscovery.uuid_count = 0;\n      \u003c----------------------preempted-----------------------------\u003e\n                        \u0027start_service_discovery\u0027\n                          // Set uuid_count to value != 0\n                          hdev-\u003ediscovery.uuid_count = uuid_count;\n                          hdev-\u003ediscovery.uuids = kmemdup(...);\n      \u003c----------------------preempted-----------------------------\u003e\n    spin_lock(\u0026hdev-\u003ediscovery.lock);\n    kfree(hdev-\u003ediscovery.uuids);\n    hdev-\u003ediscovery.uuids = NULL;\n    spin_unlock(\u0026hdev-\u003ediscovery.lock);\n\nNow uuids == NULL and uuid_count != 0.\nSo \u0027mgmt_device_found\u0027 -\u003e \u0027is_filter_match\u0027 -\u003e \u0027eir_has_uuids\u0027 receives\nnon consistent discovery state, where NULL dereference of uuids happens.\n\nTo fix it let\u0027s add discovery.lock around every read/write of uuid_count,\nuuids pair of struct members. It is also important to assign uuid_count\nvalue only after success kmemdup() allocation in\nstart_service_discovery(), otherwise uuids is NULL, because kmemdup failed,\nbut uuid_count is already assigned to non zero value.\n\nThe following panic happens:\n\n[ ] ------------[ cut here ]------------\n[ ] Unable to handle kernel NULL pointer dereference at virtual\naddress 0000000000000000\n[ ] Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP\n[ ] CPU: 0 PID: 15056 Comm: kworker/u9:2\n[ ] Workqueue: hci0 hci_rx_work\n[ ] pstate: 10400009 (nzcV daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[ ] pc : eir_has_uuids+0x2d8/0x590\n[ ] lr : is_filter_match+0x258/0x320\n...\n[ ] Call trace:\n[ ]  eir_has_uuids+0x2d8/0x590\n[ ]  is_filter_match+0x258/0x320\n[ ]  mgmt_device_found+0x5b0/0xafc\n[ ]  process_adv_report.part.0+0x8c8/0xf14\n[ ]  hci_le_adv_report_evt+0x338/0x3f0\n[ ]  hci_le_meta_evt+0x1f0/0x4c8\n[ ]  hci_event_packet+0x440/0xc9c\n[ ]  hci_rx_work+0x44c/0xaf8\n[ ]  process_one_work+0x54c/0x103c\n[ ]  worker_thread+0x6c4/0x10c4\n[ ]  kthread+0x274/0x2ec\n[ ]  ret_from_fork+0x10/0x20\n[ ] Code: 14000004 91004021 eb14003f 54000180 (f9400024)\n[ ] ---[ end trace 0000000000000000 ]---",
  "id": "GHSA-v2qr-f43f-h5vh",
  "modified": "2026-09-24T18:31:24Z",
  "published": "2026-09-24T18:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93247"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/18fda026a13c5abd6c1e0dfd3549f490b73378fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/59eecbe2f2f38d8f3e1104bd11da97f9a2c58998"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bbd262d2d750b67b15a5e1008d3848309c87e7a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c3f63610bceaa182e4683b23cc47baf36b5f1496"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee2135a14fb2a3e176149122764d293f0796b1eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f02c01ccd12cb2b8a290077d4c90f29a6e109b16"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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