{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-54120",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-54120"
  ],
  "published": "2025-12-24T13:11:50Z",
  "summary": "Bluetooth: Fix race condition in hidp_session_thread",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: Fix race condition in hidp_session_thread\n\nThere is a potential race condition in hidp_session_thread that may\nlead to use-after-free. For instance, the timer is active while\nhidp_del_timer is called in hidp_session_thread(). After hidp_session_put,\nthen 'session' will be freed, causing kernel panic when hidp_idle_timeout\nis running.\n\nThe solution is to use del_timer_sync instead of del_timer.\n\nHere is the call trace:\n\n? hidp_session_probe+0x780/0x780\ncall_timer_fn+0x2d/0x1e0\n__run_timers.part.0+0x569/0x940\nhidp_session_probe+0x780/0x780\ncall_timer_fn+0x1e0/0x1e0\nktime_get+0x5c/0xf0\nlapic_next_deadline+0x2c/0x40\nclockevents_program_event+0x205/0x320\nrun_timer_softirq+0xa9/0x1b0\n__do_softirq+0x1b9/0x641\n__irq_exit_rcu+0xdc/0x190\nirq_exit_rcu+0xe/0x20\nsysvec_apic_timer_interrupt+0xa1/0xc0",
  "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": [
        "1:6.1.21-1+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": "6.1.25"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-54120"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/152f47bd6b995e0e98c85672f6d19894bc287ef2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5f3d214d19899183d4e0cce7552998262112e4ab"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8a99e6200c38b78a45dcd12a6bdc43fdf4dc36be"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f7ec5ca433ceead8d9d78fd2febff094f289441d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0efb276d5848a3accc37c6f41b85e442c4768169"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f6719fd8f409fa1da8dc956e93822d25e1e8b360"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/248af9feca062a4ca9c3f2ccf67056c8a5eb817f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c95930abd687fcd1aa040dc4fe90dff947916460"
    }
  ],
  "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": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - The vulnerable HIDP session and its idle timer are driven entirely by a Bluetooth peer's traffic and link teardown, so the attacker must be within Bluetooth radio range of the host. Bluetooth-reachable code is scored Adjacent.\nAC:L - The attacker controls both sides of the race: the idle timer is re-armed on every input report it sends (so expiry timing is known precisely), and it triggers the session-thread exit at that exact moment via an L2CAP disconnect or a VIRTUAL_CABLE_UNPLUG control message. The attempt can be repeated indefinitely by reconnecting.\nPR:N - The attacker needs no account or privileges on the target host; it acts purely as a Bluetooth HID peripheral, and Linux HID hosts of this era accepted HID connections from unbonded peers. All required actions are ordinary HIDP protocol traffic.\nUI:N - The HIDP session is established and torn down by the Bluetooth daemon automatically in response to the peer's connection and its subsequent disconnect/unplug; no victim action is required at any point.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - hidp_idle_timeout() reads pointer fields (intr_sock/ctrl_sock) out of the freed hidp_session and follows them, and the resulting UAF primitive over a plain-kfree'd heap object can be leveraged with heap grooming to disclose arbitrary kernel memory.\nI:H - The callback writes EUNATCH through a pointer read from freed memory and performs wake_up_interruptible() on a waitqueue head taken from that freed object, giving both a controlled write and an indirect call through an attacker-groomable function pointer \u2014 sufficient for control-flow hijack.\nA:H - The reported symptom is a kernel panic from the timer callback running against a freed session; any such use-after-free reliably oopses the kernel and can be triggered repeatedly by a nearby device."
    }
  }
}