{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64434",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64434"
  ],
  "published": "2026-07-25T08:51:45Z",
  "summary": "Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref\n\nl2cap_chan_timeout() runs asynchronously and accesses chan->conn. If\nthe connection is torn down while the timer is running or pending,\nchan->conn can be freed, leading to a use-after-free when the timer\nworker attempts to lock conn->lock:\n\n| BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]\n| BUG: KASAN: slab-use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]\n| BUG: KASAN: slab-use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]\n| BUG: KASAN: slab-use-after-free in mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318\n| Write of size 8 at addr ffff8881298d9550 by task kworker/2:1/83\n|\n| CPU: 2 UID: 0 PID: 83 Comm: kworker/2:1 Not tainted 7.1.0-rc6-next-20260601-dirty #6 PREEMPT(full)\n| Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014\n| Workqueue: events l2cap_chan_timeout\n| Call Trace:\n|  <TASK>\n|  instrument_atomic_read_write include/linux/instrumented.h:112 [inline]\n|  atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:4456 [inline]\n|  __mutex_trylock_fast kernel/locking/mutex.c:161 [inline]\n|  mutex_lock+0x4f/0xa0 kernel/locking/mutex.c:318\n|  l2cap_chan_timeout+0x5d/0x1b0 net/bluetooth/l2cap_core.c:422\n|  process_one_work kernel/workqueue.c:3326 [inline]\n|  process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409\n|  worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490\n|  kthread+0x346/0x430 kernel/kthread.c:436\n|  ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158\n|  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n|  </TASK>\n|\n| Allocated by task 320:\n|  l2cap_conn_add+0xa7/0x820 net/bluetooth/l2cap_core.c:7075\n|  l2cap_connect_cfm+0xdb/0xd70 net/bluetooth/l2cap_core.c:7452\n|  hci_connect_cfm include/net/bluetooth/hci_core.h:2139 [inline]\n|  hci_remote_features_evt+0x52f/0x9f0 net/bluetooth/hci_event.c:3760\n|  hci_event_func net/bluetooth/hci_event.c:7796 [inline]\n|  hci_event_packet+0x561/0xa70 net/bluetooth/hci_event.c:7847\n|  hci_rx_work+0x370/0x890 net/bluetooth/hci_core.c:4040\n|  process_one_work kernel/workqueue.c:3326 [inline]\n|  process_scheduled_works+0x7c8/0xfb0 kernel/workqueue.c:3409\n|  worker_thread+0x8a9/0xcf0 kernel/workqueue.c:3490\n|  kthread+0x346/0x430 kernel/kthread.c:436\n|  ret_from_fork+0x1a3/0x470 arch/x86/kernel/process.c:158\n|  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n|\n| Freed by task 322:\n|  hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]\n|  hci_conn_hash_flush+0x101/0x1f0 net/bluetooth/hci_conn.c:2736\n|  hci_dev_close_sync+0x889/0xde0 net/bluetooth/hci_sync.c:5405\n|  hci_dev_do_close net/bluetooth/hci_core.c:502 [inline]\n|  hci_unregister_dev+0x1f7/0x370 net/bluetooth/hci_core.c:2679\n|  vhci_release+0x12a/0x180 drivers/bluetooth/hci_vhci.c:690\n|  __fput+0x369/0x890 fs/file_table.c:510\n|  task_work_run+0x160/0x1d0 kernel/task_work.c:233\n|  get_signal+0xf5b/0x1120 kernel/signal.c:2810\n|  arch_do_signal_or_restart+0x4d/0x600 arch/x86/kernel/signal.c:337\n|  __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]\n|  exit_to_user_mode_loop+0x85/0x510 kernel/entry/common.c:98\n|  do_syscall_64+0x263/0x3d0 arch/x86/entry/syscall_64.c:100\n|  entry_SYSCALL_64_after_hwframe+0x77/0x7f\n|\n| The buggy address belongs to the object at ffff8881298d9400\n|  which belongs to the cache kmalloc-512 of size 512\n| The buggy address is located 336 bytes inside of\n|  freed 512-byte region [ffff8881298d9400, ffff8881298d9600)\n\nFix it by having chan->conn hold a reference to l2cap_conn (via\nl2cap_conn_get) when the channel is added to the connection, and\nreleasing it in the channel destructor. This ensures the l2cap_conn\nremains alive as long as the channel exists.\n\nA new FLAG_DEL channel flag is introduced to indicate that the ch\n---truncated---",
  "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:12",
        "name": "linux"
      },
      "versions": [
        "1:6.12.93-1+rpt1",
        "1:6.12.96-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-2712",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-v6",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-v7",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-v7l",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-v8",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.93+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.93-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-2712",
            "binary_version": "1:6.12.96-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-v6",
            "binary_version": "1:6.12.96-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-v7",
            "binary_version": "1:6.12.96-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-v7l",
            "binary_version": "1:6.12.96-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-v8",
            "binary_version": "1:6.12.96-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.12.96+rpt-rpi-v8-rt",
            "binary_version": "1:6.12.96-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.12.93-1+rpt1": {
            "linux_commit": "d8ab4e908235da7727f22dd36ad5af224671677d",
            "upstream_version": "6.12.93",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.97"
          },
          "1:6.12.96-1+rpt1": {
            "linux_commit": "ae161617d7a4552fa91d03626b8d9f3696d17481",
            "upstream_version": "6.12.96",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.12.97"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64434"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8f90405a4a6f1f1880dc07996b47bf57c712bd8a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8922c7940bae9ce4b1736dddb6362370793835c2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/91047a4396a8b1857a6f712a90cf33ec0012b189"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0b0e2bf39cf99e458d991b9df253727e036a7d7d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d3b739db5dc6f688a60d56da872fabaf65246032"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/50c38d9f42a529691e4e67ea9cedf4f0bfc8d277"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b66774b48dd98f07254951f74ea6f513efe7ff8b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-19T16:47:12Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - An unauthenticated Bluetooth peer within radio range can reach the vulnerable worker by creating a half-configured L2CAP channel and subsequently terminating the ACL connection.\nAC:L - The attacker controls both channel creation and connection teardown, can leave the 40-second channel timer armed, and can repeat or parallelize attempts to win the race.\nPR:N - The BR/EDR signaling path processes incoming L2CAP requests before application acceptance, and an SDP listener permits this path without pairing or authentication.\nUI:N - Exploitation requires no victim action because an already-running Bluetooth service and the kernel independently process the connection, timer, and disconnection.\nS:U - The UAF compromises the host kernel within the same security authority and does not inherently cross a VM, IOMMU, or comparable boundary.\nC:H - The freed kmalloc object can be reclaimed with attacker-influenced contents, allowing the UAF to support kernel-memory disclosure primitives.\nI:H - The worker performs mutex writes into the freed allocation, enabling heap corruption and potentially arbitrary write or kernel control-flow hijacking after heap grooming.\nA:H - The stale mutex access can corrupt memory, trigger an oops or panic, and can be retriggered by a nearby Bluetooth peer."
    }
  }
}