{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53252",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53252"
  ],
  "published": "2025-09-15T14:48:04Z",
  "summary": "Bluetooth: use RCU for hci_conn_params and iterate safely in hci_sync",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: use RCU for hci_conn_params and iterate safely in hci_sync\n\nhci_update_accept_list_sync iterates over hdev->pend_le_conns and\nhdev->pend_le_reports, and waits for controller events in the loop body,\nwithout holding hdev lock.\n\nMeanwhile, these lists and the items may be modified e.g. by\nle_scan_cleanup. This can invalidate the list cursor or any other item\nin the list, resulting to invalid behavior (eg use-after-free).\n\nUse RCU for the hci_conn_params action lists. Since the loop bodies in\nhci_sync block and we cannot use RCU or hdev->lock for the whole loop,\ncopy list items first and then iterate on the copy. Only the flags field\nis written from elsewhere, so READ_ONCE/WRITE_ONCE should guarantee we\nread valid values.\n\nFree params everywhere with hci_conn_params_free so the cleanup is\nguaranteed to be done properly.\n\nThis fixes the following, which can be triggered e.g. by BlueZ new\nmgmt-tester case \"Add + Remove Device Nowait - Success\", or by changing\nhci_le_set_cig_params to always return false, and running iso-tester:\n\n==================================================================\nBUG: 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)\nRead of size 8 at addr ffff888001265018 by task kworker/u3:0/32\n\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014\nWorkqueue: hci0 hci_cmd_sync_work\nCall Trace:\n<TASK>\ndump_stack_lvl (./arch/x86/include/asm/irqflags.h:134 lib/dump_stack.c:107)\nprint_report (mm/kasan/report.c:320 mm/kasan/report.c:430)\n? __virt_addr_valid (./include/linux/mmzone.h:1915 ./include/linux/mmzone.h:2011 arch/x86/mm/physaddr.c:65)\n? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)\nkasan_report (mm/kasan/report.c:538)\n? hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)\nhci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2536 net/bluetooth/hci_sync.c:2723 net/bluetooth/hci_sync.c:2841)\n? __pfx_hci_update_passive_scan_sync (net/bluetooth/hci_sync.c:2780)\n? mutex_lock (kernel/locking/mutex.c:282)\n? __pfx_mutex_lock (kernel/locking/mutex.c:282)\n? __pfx_mutex_unlock (kernel/locking/mutex.c:538)\n? __pfx_update_passive_scan_sync (net/bluetooth/hci_sync.c:2861)\nhci_cmd_sync_work (net/bluetooth/hci_sync.c:306)\nprocess_one_work (./arch/x86/include/asm/preempt.h:27 kernel/workqueue.c:2399)\nworker_thread (./include/linux/list.h:292 kernel/workqueue.c:2538)\n? __pfx_worker_thread (kernel/workqueue.c:2480)\nkthread (kernel/kthread.c:376)\n? __pfx_kthread (kernel/kthread.c:331)\nret_from_fork (arch/x86/entry/entry_64.S:314)\n</TASK>\n\nAllocated by task 31:\nkasan_save_stack (mm/kasan/common.c:46)\nkasan_set_track (mm/kasan/common.c:52)\n__kasan_kmalloc (mm/kasan/common.c:374 mm/kasan/common.c:383)\nhci_conn_params_add (./include/linux/slab.h:580 ./include/linux/slab.h:720 net/bluetooth/hci_core.c:2277)\nhci_connect_le_scan (net/bluetooth/hci_conn.c:1419 net/bluetooth/hci_conn.c:1589)\nhci_connect_cis (net/bluetooth/hci_conn.c:2266)\niso_connect_cis (net/bluetooth/iso.c:390)\niso_sock_connect (net/bluetooth/iso.c:899)\n__sys_connect (net/socket.c:2003 net/socket.c:2020)\n__x64_sys_connect (net/socket.c:2027)\ndo_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)\n\nFreed by task 15:\nkasan_save_stack (mm/kasan/common.c:46)\nkasan_set_track (mm/kasan/common.c:52)\nkasan_save_free_info (mm/kasan/generic.c:523)\n__kasan_slab_free (mm/kasan/common.c:238 mm/kasan/common.c:200 mm/kasan/common.c:244)\n__kmem_cache_free (mm/slub.c:1807 mm/slub.c:3787 mm/slub.c:3800)\nhci_conn_params_del (net/bluetooth/hci_core.c:2323)\nle_scan_cleanup (net/bluetooth/hci_conn.c:202)\nprocess_one_work (./arch/x86/include/asm/preempt.\n---truncated---",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.42"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53252"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/13ad45ad14df992a6754a130a19abc8c142d54e2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cef88a0fd8e9c2e838162fbb742b3e713b811a7e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/195ef75e19287b4bc413da3e3e3722b030ac881e"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:24:39Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The UAF is reached via local AF_BLUETOOTH paths (L2CAP/ISO connect or MGMT add/remove device) that mutate pend_le_conns while hci_update_accept_list_sync runs; it is not triggered by processing packets from an adjacent Bluetooth peer.\nAC:L - The attacker controls both sides of the race by starting LE connects (queueing accept-list sync) and aborting/timing them out (le_scan_cleanup freeing params), and the race window is large because the vulnerable loop blocks on HCI commands for up to HCI_CMD_TIMEOUT (2s) per entry.\nPR:L - Unprivileged users can create L2CAP SEQPACKET and ISO sockets with no capability check and call into hci_connect_le_scan, which adds hci_conn_params to pend_le_conns; MGMT add/remove needs CAP_NET_ADMIN but is not required for this path.\nUI:N - Exploitation requires only the attacker's own socket connect/abort operations; no separate victim action is needed.\nS:U - This is a standard in-kernel UAF enabling privilege escalation within the host kernel's security authority, not a cross-boundary escape.\nC:H - Slab use-after-free of hci_conn_params during list iteration allows reclaim/spray of the freed object and arbitrary kernel memory disclosure.\nI:H - The same UAF enables heap spraying and corrupted list/object writes that can be leveraged for arbitrary write and control-flow hijacking.\nA:H - The demonstrated KASAN slab-use-after-free in hci_update_passive_scan_sync causes kernel oops/crash and can be triggered repeatedly."
    }
  }
}