Bluetooth: RFCOMM: serialize security confirmation handling

{
  "id": "6fdc54a34d9525348630d68ad8f3c4685ae0b00b81aad157d86ebb5f74e2cf8d",
  "url": "https://osv.dev/vulnerability/CVE-2026-89569",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bluetooth: RFCOMM: serialize security confirmation handling",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: serialize security confirmation handling rfcomm_security_cfm() looks up a session on session_list and then walks its DLC list without holding rfcomm_mutex. Since RFCOMM session teardown uses rfcomm_mutex, krfcommd can close and free the same session and DLCs concurrently: hci_rx_work krfcommd ----------- --------- rfcomm_session_get() rfcomm_lock() rfcomm_session_close() rfcomm_dlc_unlink() rfcomm_session_del() kfree(s) rfcomm_unlock() walk s->dlcs The callback can then read a freed session list head and touch freed DLCs while updating their flags or timers. Serialize the session lookup and DLC traversal in rfcomm_security_cfm() with rfcomm_mutex. This matches the existing RFCOMM session lifetime rules and prevents concurrent rfcomm_session_del() / rfcomm_dlc_unlink() from tearing the objects down while the callback is using them. KASAN reported: BUG: KASAN: slab-use-after-free in rfcomm_security_cfm+0x41c/0x440 Read of size 8 at addr ffff888111fb3960 by task kworker/u17:1/89 Workqueue: hci0 hci_rx_work Call Trace: rfcomm_security_cfm+0x41c/0x440 hci_encrypt_cfm+0x139/0x590 hci_encrypt_change_evt+0x37b/0xc40 hci_event_packet+0x71b/0xb20 hci_rx_work+0x293/0x730 Allocated by task 69: rfcomm_session_add+0x9e/0x2f0 rfcomm_run+0x44b/0x41e0 Freed by task 69: kfree+0x131/0x3c0 rfcomm_session_del+0x188/0x220 rfcomm_run+0x1985/0x41e0",
    "evidence": "osv:CVE-2026-89569",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
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            "value": "5.15.221",
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          {
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        "affected_versions": []
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    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89569",
      "aliases": [
        "CVE-2026-89569"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
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          "database_specific": {
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          "package": {
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:50.209008498Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1b7841ffad08e911e8c4b9470f3fa08423568940",
        "https://git.kernel.org/stable/c/3873f3449701b3dc98cba577923be6493598e7a1",
        "https://git.kernel.org/stable/c/62ce8b33eb238cf18c15207332fbdc26d858f592",
        "https://git.kernel.org/stable/c/759c185d0bbdb131357408f50b8735e04ed3caff",
        "https://git.kernel.org/stable/c/7ded3264106418c6456ccceaafd9fda596ce12c3",
        "https://git.kernel.org/stable/c/82425b14f0fb22e46cfddc56d6465570f5ed0ce6",
        "https://git.kernel.org/stable/c/946d76db77ee5f922968ce558629ae47b381e3fc",
        "https://git.kernel.org/stable/c/fbf7961964a6e93360179f64712320ae9a1e9577",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89569.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89569",
        "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/2026/89xxx/CVE-2026-89569.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89569",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518940,
  "published_at": "2026-09-11T19:44:38.838+00:00"
}