Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync

{
  "id": "b3233e7b9cedb5ca999cc715bd867475a7a69d6cb7a2b51ae32092b0a9201e86",
  "url": "https://osv.dev/vulnerability/CVE-2023-53252",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync hci_update_accept_list_sync iterates over hdev->pend_le_conns and hdev->pend_le_reports, and waits for controller events in the loop body, without holding hdev lock. Meanwhile, these lists and the items may be modified e.g. by le_scan_cleanup. This can invalidate the list cursor or any other item in the list, resulting to invalid behavior (eg use-after-free). Use RCU for the hci_conn_params action lists. Since the loop bodies in hci_sync block and we cannot use RCU or hdev->lock for the whole loop, copy list items first and then iterate on the copy. Only the flags field is written from elsewhere, so READ_ONCE/WRITE_ONCE should guarantee we read valid values. Free params everywhere with hci_conn_params_free so the cleanup is guaranteed to be done properly. This fixes the following, which can be triggered e.g. by BlueZ new mgmt-tester case \"Add + Remove Device Nowait - Success\", or by changing hci_le_set_cig_params to always return false, and running iso-tester: ================================================================== BUG: KASAN: slab-use-after-free in hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841) Read of size 8 at addr ffff888001265018 by task kworker/u3:0/32 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: hci0 hc",
    "evidence": "osv:CVE-2023-53252",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.42",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.4.7",
            "evidence": "/affected/1/ranges"
          }
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        "affected_versions": []
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    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-53252",
      "aliases": [
        "CVE-2023-53252"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
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      "affected": [
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                {
                  "fixed": "13ad45ad14df992a6754a130a19abc8c142d54e2"
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                {
                  "fixed": "cef88a0fd8e9c2e838162fbb742b3e713b811a7e"
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                  "fixed": "195ef75e19287b4bc413da3e3e3722b030ac881e"
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          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.17.0"
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                {
                  "fixed": "6.1.42"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "6.2.0"
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                  "fixed": "6.4.7"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53252.json"
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      ],
      "modified": "2026-10-28T02:30:43.960165930Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/13ad45ad14df992a6754a130a19abc8c142d54e2",
        "https://git.kernel.org/stable/c/195ef75e19287b4bc413da3e3e3722b030ac881e",
        "https://git.kernel.org/stable/c/cef88a0fd8e9c2e838162fbb742b3e713b811a7e",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53252.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53252",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53252.json"
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    "related_cves": [
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        "value": "CVE-2023-53252",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 511680,
  "published_at": "2025-09-15T14:46:21.72+00:00"
}