{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-80683",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-80683"
  ],
  "published": "2026-08-28T06:53:24Z",
  "summary": "Bluetooth: SCO: give the socket its own sco_conn reference",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: SCO: give the socket its own sco_conn reference\n\nsco_conn_del() drops a reference it does not own. It takes one transient\nreference via sco_conn_hold_unless_zero() and releases it with the\nsco_conn_put() that follows sco_sock_hold(); the additional put in the\n!sk branch releases a second one:\n\n    conn = sco_conn_hold_unless_zero(conn);\n    ...\n    sk = sco_sock_hold(conn);\n    sco_conn_unlock(conn);\n    sco_conn_put(conn);\n\n    if (!sk) {\n            sco_conn_put(conn);\n            return;\n    }\n\nWhen close() races the controller's Disconnection Complete, sco_chan_del()\nclears conn->sk and drops the socket's reference while sco_conn_del() is\nrunning. sco_conn_del() then sees sk == NULL, its own put drops the count\nto zero and frees the conn, and the second put writes to the freed kref:\n\n    BUG: KASAN: slab-use-after-free in sco_conn_put.part.0+0x1a/0x190\n    Write of size 4 at addr ffff8881099dec74 by task kworker/u17:3/413\n    Workqueue: hci1 hci_rx_work\n    Call Trace:\n     sco_conn_put.part.0+0x1a/0x190\n     hci_disconn_complete_evt+0x1ee/0x3e0\n     hci_event_packet+0x54a/0x650\n     hci_rx_work+0x321/0x3d0\n    Allocated by task 413:\n     sco_conn_add+0x72/0x1a0\n     sco_connect_cfm+0x88/0x670\n    Freed by task 413:\n     sco_conn_del.isra.0+0x3f/0xf0\n     hci_disconn_complete_evt+0x1ee/0x3e0\n    refcount_t: underflow; use-after-free.\n\nThe root cause is that the socket stores the connection without holding a\nreference of its own. __sco_chan_add() does:\n\n    sco_pi(sk)->conn = conn;\n\nso the socket borrows whatever reference its caller happened to hold, and\nthe callers paper over that with ad-hoc holds and puts. Give the socket a\ncounted reference instead: __sco_chan_add() takes one and it is released\ntogether with the channel (sco_chan_del()) and in sco_sock_destruct().\nWith the socket holding its own reference, sco_conn_del() no longer needs\nthe extra put and the redundant hold in sco_conn_ready() goes away.\n\nMaking the socket own its reference means the connection is now actually\nfreed on the error paths of sco_connect() where it used to leak, which in\nturn runs sco_conn_free() and its hci_conn_drop(conn->hcon). To keep the\nhci_conn accounting balanced, make that ownership explicit as well:\nsco_conn_add() consumes one hci_conn reference and the sco_conn owns it for\nits lifetime. sco_connect() hands over the reference returned by\nhci_connect_sco() and no longer drops it on the error paths;\nsco_connect_cfm(), which is not given a reference, takes one with\nhci_conn_hold() before handing it to sco_conn_add() (and drops it again if\nthe allocation fails); and the explicit hci_conn_hold() in sco_conn_ready()\nis removed. Every reference then has a single, clear owner.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:13",
        "name": "linux"
      },
      "versions": [
        "1:6.18.29-1+rpt1",
        "1:6.18.33-1+rpt1",
        "1:6.18.34-1+rpt1",
        "1:6.18.39-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
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            "binary_version": "1:6.18.29-1+rpt1"
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          {
            "binary_name": "linux-image-6.18.29+rpt-rpi-v8",
            "binary_version": "1:6.18.29-1+rpt1"
          },
          {
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            "binary_version": "1:6.18.29-1+rpt1"
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            "binary_name": "linux-image-6.18.33+rpt-rpi-2712",
            "binary_version": "1:6.18.33-1+rpt1"
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      "database_specific": {
        "per_version": {
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            "linux_commit": "66318c5b5cd8145a662303af12ed39ac07eb27cc",
            "upstream_version": "6.18.29",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.18.44"
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  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-80683"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a33bc07b4730b6cd5681ac77d18ae0de3e739690"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8fe627192fa5da7157f9a48608f13c04b6373e43"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/abd93c85c8667add738ee82aeab95dd9fc8265a2"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-29T06:25:05Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - The UAF is triggered in sco_conn_del() from hci_disconn_complete_evt on hci_rx_work when the Bluetooth controller reports SCO/eSCO teardown, which is driven by an in-range peer disconnect; Bluetooth SCO is an adjacent-radio protocol path, not a local-only syscall entry point.\nAC:L - The failure is a close()-versus-Disconnection-Complete race where the attacker controls both sides by concurrently closing the SCO socket while inducing HCI disconnect (local threads or a nearby peer hanging up), and can repeat connect/disconnect cycles until the window is hit.\nPR:N - An adjacent Bluetooth peer can send the disconnect that produces Disconnection Complete without any Linux credentials on the victim, and SCO sockets have no capability gate; only an active SCO session on init_net is needed, not root or CAP_NET_ADMIN.\nUI:N - Exploitation does not require victim interaction beyond an already-active SCO link (headset/call); the attacker can time peer-initiated disconnects against automatic socket teardown without social engineering or manual victim steps.\nS:U - The refcount use-after-free corrupts kernel Bluetooth connection state within the same kernel security authority; it is standard kernel memory corruption, not a VM escape, IOMMU bypass, or other cross-scope boundary violation.\nC:H - sco_conn_del() performs a double sco_conn_put() that writes to a freed kref (4-byte slab UAF), enabling heap reuse and arbitrary kernel memory disclosure primitives consistent with kernel use-after-free confidentiality impact.\nI:H - The post-free kref decrement is a controlled kernel heap write that can be groomed via repeated SCO connect/close and disconnect cycles to corrupt adjacent slab objects and achieve arbitrary write or control-flow hijack.\nA:H - The bug reliably triggers kernel KASAN slab-use-after-free and refcount underflow on hci_rx_work during disconnect handling, producing oops/panic, and can be retriggered to deny service."
    }
  }
}