{
  "cveId": "CVE-2026-48686",
  "url": "https://patchblox.com/security/cve/CVE-2026-48686",
  "summary": "CVE-2026-48686 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 a stack-based buffer overflow in the BGP NLRI (Network Layer Reac...",
  "description": "FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decode_bgp_subnet_encoding_ipv4_raw() in src/bgp_protocol.cpp reads prefix_bit_length directly from the BGP packet (line 99) without validating it is \u003C= 32 for IPv4 prefixes. This value is passed to how_much_bytes_we_need_for_storing_certain_subnet_mask() which computes ceil(prefix_bit_length / 8), returning up to 32 bytes for a prefix_bit_length of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32_t stack variable (prefix_ipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefix_bit_length is passed to convert_cidr_to_binary_netmask_local_function_copy() (line 111), where a shift of (32 - cidr) with cidr \u003E 32 causes undefined behavior.",
  "published": "2026-05-26T09:16:00Z",
  "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": 0.00565,
  "epssPercentile": 0.47174,
  "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-2026-48686",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-48686",
      "released": "2026-06-24T14:07:24Z"
    },
    {
      "platform": "linux",
      "product": "fastnetmon",
      "release": "Debian 14",
      "fixedVersion": "1.2.9-1",
      "fix": "DEBIAN-CVE-2026-48686",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-48686",
      "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": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}