{
  "cveId": "CVE-2026-48689",
  "url": "https://patchblox.com/security/cve/CVE-2026-48689",
  "summary": "CVE-2026-48689 is fixed in fastnetmon on 1 platform, first by fastnetmon 1.2.8\u002Bgit20250911-2ubuntu0.1~esm1, released May 26, 2026. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "fastnetmon: FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in the dynamic_binary_bu...",
  "description": "FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in the dynamic_binary_buffer_t class (src/dynamic_binary_buffer.hpp). Five methods (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) use an incorrect bounds check of the form \u0027if (offset \u002B length \u003E maximum_internal_storage_size \u002B 1)\u0027 instead of the correct \u0027if (offset \u002B length \u003E maximum_internal_storage_size)\u0027. This allows writing exactly one byte past the end of the heap-allocated buffer. The class is used pervasively in BGP message encoding/decoding, NetFlow template processing, and Flow Spec NLRI construction. An attacker who can send network traffic (NetFlow, sFlow, IPFIX, or BGP) to a FastNetMon instance can trigger this overflow, potentially achieving arbitrary code execution by corrupting heap metadata. Notably, the append_byte() method uses the correct bounds check, confirming the inconsistency.",
  "published": "2026-05-26T12:16:00Z",
  "severity": "critical",
  "cvss": 9.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00677,
  "epssPercentile": 0.52493,
  "priority": "Urgent",
  "priorityTier": 2,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "fastnetmon",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.2.9-0\u002Bdeb13u1",
      "fix": "DEBIAN-CVE-2026-48689",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-48689",
      "released": "2026-06-24T14:07:24Z"
    },
    {
      "platform": "linux",
      "product": "fastnetmon",
      "release": "Debian 14",
      "fixedVersion": "1.2.9-1",
      "fix": "DEBIAN-CVE-2026-48689",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-48689",
      "released": "2026-06-24T14:07:24Z"
    },
    {
      "platform": "linux",
      "product": "fastnetmon",
      "release": "Ubuntu 24.04.5 LTS (noble)",
      "fixedVersion": "1.2.6-1ubuntu0.1~esm1",
      "fix": "fastnetmon 1.2.6-1ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-noble-fastnetmon-1.2.6-1ubuntu0.1-esm1",
      "released": "2026-06-24T14:07:41Z"
    },
    {
      "platform": "linux",
      "product": "fastnetmon",
      "release": "Ubuntu 26.04.1 LTS (resolute)",
      "fixedVersion": "1.2.8\u002Bgit20250911-2ubuntu0.1~esm1",
      "fix": "fastnetmon 1.2.8\u002Bgit20250911-2ubuntu0.1~esm1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-resolute-fastnetmon-1.2.8-git20250911-2ubuntu0.1-esm1",
      "released": "2026-05-26T12:16:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}