{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-39987",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-39987"
  ],
  "published": "2025-10-15T07:57:23Z",
  "summary": "can: hi311x: populate ndo_change_mtu() to prevent buffer overflow",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: hi311x: populate ndo_change_mtu() to prevent buffer overflow\n\nSending an PF_PACKET allows to bypass the CAN framework logic and to\ndirectly reach the xmit() function of a CAN driver. The only check\nwhich is performed by the PF_PACKET framework is to make sure that\nskb->len fits the interface's MTU.\n\nUnfortunately, because the sun4i_can driver does not populate its\nnet_device_ops->ndo_change_mtu(), it is possible for an attacker to\nconfigure an invalid MTU by doing, for example:\n\n  $ ip link set can0 mtu 9999\n\nAfter doing so, the attacker could open a PF_PACKET socket using the\nETH_P_CANXL protocol:\n\n\tsocket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL))\n\nto inject a malicious CAN XL frames. For example:\n\n\tstruct canxl_frame frame = {\n\t\t.flags = 0xff,\n\t\t.len = 2048,\n\t};\n\nThe CAN drivers' xmit() function are calling can_dev_dropped_skb() to\ncheck that the skb is valid, unfortunately under above conditions, the\nmalicious packet is able to go through can_dev_dropped_skb() checks:\n\n  1. the skb->protocol is set to ETH_P_CANXL which is valid (the\n     function does not check the actual device capabilities).\n\n  2. the length is a valid CAN XL length.\n\nAnd so, hi3110_hard_start_xmit() receives a CAN XL frame which it is\nnot able to correctly handle and will thus misinterpret it as a CAN\nframe. The driver will consume frame->len as-is with no further\nchecks.\n\nThis can result in a buffer overflow later on in hi3110_hw_tx() on\nthis line:\n\n\tmemcpy(buf + HI3110_FIFO_EXT_DATA_OFF,\n\t       frame->data, frame->len);\n\nHere, frame->len corresponds to the flags field of the CAN XL frame.\nIn our previous example, we set canxl_frame->flags to 0xff. Because\nthe maximum expected length is 8, a buffer overflow of 247 bytes\noccurs!\n\nPopulate net_device_ops->ndo_change_mtu() to ensure that the\ninterface's MTU can not be set to anything bigger than CAN_MTU. By\nfixing the root cause, this prevents the buffer overflow.",
  "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": "6.1.155",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-39987"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f2c247e9581024d8b3dd44cbe086bf2bebbef42c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8f351db6b2367991f0736b2cff082f5de4872113"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7ab85762274c0fa997f0ef9a2307b2001aae43c4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/57d332ce8c921d0e340650470bb0c1d707f216ee"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/be1b25005fd0f9d4e78bec6695711ef87ee33398"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/def814b4ba31b563584061d6895d5ff447d5bc14"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e77fdf9e33a83a08f04ab0cb68c19ddb365a622f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ac1c7656fa717f29fac3ea073af63f0b9919ec9a"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z"
  }
}