CVE-2026-74509 (GCVE-0-2026-74509)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-27 12:39
Severity ?
8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Fix advertising data UAFs hci_find_adv_instance() returns an adv_info pointer that is valid only while hdev->lock is held. The advertising command-sync paths perform instance lookups without that lock and, in some cases, retain the pointer while waiting for a controller response. An advertising termination event can therefore interleave as follows: hci_cmd_sync_work hci_rx_work hci_find_adv_instance() __hci_cmd_sync_status() wait for controller reply hci_dev_lock() hci_remove_adv_instance() kfree(adv) adv->scan_rsp_changed = false KASAN reported: BUG: KASAN: slab-use-after-free in hci_set_ext_scan_rsp_data_sync+0x2e1/0x300 Write of size 1 at addr ffff88810a45d21d by task kworker/u17:0/88 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_set_ext_scan_rsp_data_sync+0x2e1/0x300 hci_schedule_adv_instance_sync+0x390/0x4c0 hci_cmd_sync_work+0x173/0x300 Allocated by task 87: hci_add_adv_instance+0x538/0xac0 add_advertising+0x885/0x1160 Freed by task 89: kfree+0x131/0x3c0 hci_remove_adv_instance+0x1d8/0x3b0 hci_le_ext_adv_term_evt+0x17b/0x730 Protect the instance lookup and payload construction in the extended advertising, scan response, and periodic advertising data paths. Snapshot the advertising parameters under hdev->lock, but release the lock before waiting for the controller. Clear advertising-data dirty bits before issuing their commands and restore them after a failure using a fresh lookup. Likewise, update the reported transmit power through a fresh lookup after the parameter command completes. No adv_info pointer then survives an HCI command wait.
References
Impacted products
Vendor Product Version
Linux Linux Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: cba6b758711cab946c787f7c15be92cc749b8e1f
Version: 42fe380baaaccbe635c34ca07b29d19b9ec2498d
Version: 5.15.210   ≤
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_sync.c"
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              "version": "6.18.44",
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              "version": "7.1.8",
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            },
            {
              "lessThanOrEqual": "*",
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              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.17",
                  "vulnerable": true
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              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: Fix advertising data UAFs\n\nhci_find_adv_instance() returns an adv_info pointer that is valid only\nwhile hdev-\u003elock is held.  The advertising command-sync paths perform\ninstance lookups without that lock and, in some cases, retain the pointer\nwhile waiting for a controller response.\n\nAn advertising termination event can therefore interleave as follows:\n\n  hci_cmd_sync_work                 hci_rx_work\n  hci_find_adv_instance()\n  __hci_cmd_sync_status()\n    wait for controller reply       hci_dev_lock()\n                                    hci_remove_adv_instance()\n                                      kfree(adv)\n  adv-\u003escan_rsp_changed = false\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in hci_set_ext_scan_rsp_data_sync+0x2e1/0x300\n  Write of size 1 at addr ffff88810a45d21d by task kworker/u17:0/88\n  Workqueue: hci0 hci_cmd_sync_work\n  Call Trace:\n   hci_set_ext_scan_rsp_data_sync+0x2e1/0x300\n   hci_schedule_adv_instance_sync+0x390/0x4c0\n   hci_cmd_sync_work+0x173/0x300\n  Allocated by task 87:\n   hci_add_adv_instance+0x538/0xac0\n   add_advertising+0x885/0x1160\n  Freed by task 89:\n   kfree+0x131/0x3c0\n   hci_remove_adv_instance+0x1d8/0x3b0\n   hci_le_ext_adv_term_evt+0x17b/0x730\n\nProtect the instance lookup and payload construction in the extended\nadvertising, scan response, and periodic advertising data paths.  Snapshot\nthe advertising parameters under hdev-\u003elock, but release the lock before\nwaiting for the controller.\n\nClear advertising-data dirty bits before issuing their commands and\nrestore them after a failure using a fresh lookup.  Likewise, update the\nreported transmit power through a fresh lookup after the parameter command\ncompletes.  No adv_info pointer then survives an HCI command wait."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - The bug is in the Bluetooth HCI LE extended-advertising path; a remote/adjacent peer can deliver the LE Extended Advertising Set Terminated HCI event that frees adv_info while hci_cmd_sync_work waits on the controller during scan-response/advertising-data updates on phones and other BLE devices.\nAC:L - This is a use-after-free race between hci_cmd_sync_work and hci_rx_work where the attacker controls the terminating side by repeatedly initiating BLE connections/terminations during the up-to-2s HCI command wait, and can also drive the setup side via MGMT advertising commands.\nPR:N - An adjacent Bluetooth attacker needs no account, credentials, or capabilities on the victim; exploitation only requires the victim stack to be configuring BLE advertising (normal on Android phones, laptops, and IoT) while the attacker sends over-the-air BLE traffic to trigger hci_le_ext_adv_term_evt.\nUI:N - No deliberate victim action is required beyond a device running Bluetooth with LE advertising updates (common default behavior); the attacker triggers the race remotely without social engineering, file opens, or mounts.\nS:U - Impact is kernel heap corruption and potential local privilege escalation within the same kernel security domain; it does not cross a VM, container, or IOMMU boundary.\nC:H - Multiple UAF paths read freed adv_info (e.g., eir_create_scan_rsp/adv_data) and retain dangling pointers across __hci_cmd_sync_status waits, enabling slab reuse and arbitrary kernel memory disclosure via heap grooming.\nI:H - KASAN shows a post-free write to adv_info (scan_rsp_changed); similar paths write adv_data_changed and tx_power on freed objects, providing exploitable heap corruption for arbitrary kernel writes and code execution.\nA:H - Use-after-free on adv_info in hci_cmd_sync_work can cause immediate kernel oops/panic or hung BLE subsystem during advertising reconfiguration, and is reachable from unauthenticated adjacent BLE interaction on actively advertising devices."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T12:39:46.394Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/565971488191bf54a87a417abafab6ad0de72201"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4cec575a6d6f7c36808a3a0017b0675968bb06b"
        },
        {
          "url": "https://git.kernel.org/stable/c/95cdcd8c82a501931fd3ae9b3811b0b6da167e94"
        },
        {
          "url": "https://git.kernel.org/stable/c/eb1d8318764de7216e6dbba29a24d69f7ce51348"
        },
        {
          "url": "https://git.kernel.org/stable/c/b16ebdbebd2d37f4cdc590bc3e9db71fe90350a3"
        },
        {
          "url": "https://git.kernel.org/stable/c/cdc36db204ffd97b947d64374cf23a210dc74777"
        }
      ],
      "title": "Bluetooth: hci_sync: Fix advertising data UAFs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74509",
    "datePublished": "2026-08-15T12:27:31.896Z",
    "dateReserved": "2026-08-15T05:44:03.909Z",
    "dateUpdated": "2026-08-27T12:39:46.394Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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