{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:pavel-odintsov:fastnetmon:*:*:*:*:community:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.2.9"
              },
              {
                "last_affected": "1.2.9"
              }
            ],
            "source": [
              "DESCRIPTION",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "394fbe06d112f9609d3d1cb10d60cbf98347c96a"
            }
          ],
          "repo": "https://github.com/pavel-odintsov/fastnetmon",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "mitre",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48689.json"
  },
  "details": "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 'if (offset + length \u003e maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length \u003e maximum_internal_storage_size)'. 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.",
  "id": "CVE-2026-48689",
  "modified": "2026-07-15T01:49:00.690500768Z",
  "published": "2026-05-26T00:00:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/dynamic_binary_buffer.hpp"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48689.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48689"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pavel-odintsov/fastnetmon"
    },
    {
      "type": "ARTICLE",
      "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48689-dynamic-buffer-off-by-one"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}