{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2024-42280",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2024-42280"
  ],
  "published": "2024-08-17T09:11:20Z",
  "summary": "mISDN: Fix a use after free in hfcmulti_tx()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmISDN: Fix a use after free in hfcmulti_tx()\n\nDon't dereference *sp after calling dev_kfree_skb(*sp).",
  "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": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.103",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2024-42280"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/70db2c84631f50e02e6b32b543700699dd395803"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d3e4d4a98c5629ccdcb762a0ff6c82ba9738a0c3"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9460ac3dd1ae033bc2b021a458fb535a0c36ddb2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8f4030277dfb9dbe04fd78566b19931097c9d629"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4d8b642985ae24f4b3656438eb8489834a17bb80"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ddc79556641ee070d36be0de4a1f0a16a71f1fc7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7e4a539bca7d8d20f2c5d93c18cce8ef77cd78e0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/61ab751451f5ebd0b98e02276a44e23a10110402"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:52:36Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - `hfcmulti_tx()` is reached from `mISDN_sock_sendmsg()` \u2192 `handle_bmsg()`/`handle_dmsg()` on an `AF_ISDN` SOCK_DGRAM socket, i.e. a local syscall path, or from the card's IRQ/timer handler on the same host. There is no IP-network-facing consumer of this code.\nAC:L - The attacker deterministically arms the path by issuing two back-to-back `sendmsg()` calls so `bchannel_senddata()` sets `FLG_TX_NEXT`/`next_skb` (or `dchannel_senddata()` queues to `squeue`), guaranteeing `get_next_bframe()`/`get_next_dframe()` returns 1 and the post-free dereference executes. All call sites hold `hc->lock`, so there is no race to win and no memory-layout precondition.\nPR:L - `data_sock_create()` performs no `capable()` check \u2014 only `base_sock_create()` (ISDN_P_BASE/SOCK_RAW) requires `CAP_NET_RAW` \u2014 and `data_sock_bind()`/`connect_Bstack()` add no further gate, so any unprivileged local user can bind a B- or D-channel and drive the transmit path.\nUI:N - The attacker performs every step itself \u2014 socket, bind, PH_ACTIVATE_REQ, then the two queued sends \u2014 with no action required from an administrator or any other user.\nS:U - The freed object is a kernel `sk_buff` and any corruption stays within the kernel's own security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - Per the published use-after-free, the stale `(*sp)->len` sizes a `write_fifo()` read from `(*sp)->data`, pushing freed-heap contents out onto the ISDN B-/D-channel to the far end of the line; heap grooming of the reclaimed skb makes this a controllable kernel-memory disclosure.\nI:H - A use-after-free lets the attacker reclaim the freed `sk_buff` with attacker-shaped data, so the `len` and `data` fields consumed afterwards become attacker-controlled, yielding a write/pointer primitive usable for control-flow hijacking.\nA:H - Dereferencing a freed skb and DMAing/PIO-ing from a dangling `data` pointer readily oopses or panics the kernel, and the sequence can be repeated at will from an unprivileged process."
    }
  }
}