ubuntu-cve-2026-48685
Vulnerability from osv_ubuntu
Published
2026-05-26 16:16
Modified
2026-06-15 18:15
Summary
Details

FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "fastnetmon",
            "binary_version": "1.1.3+dfsg-6build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "fastnetmon",
        "purl": "pkg:deb/ubuntu/fastnetmon@1.1.3+dfsg-6build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.3+dfsg-3",
        "1.1.3+dfsg-4",
        "1.1.3+dfsg-6build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "fastnetmon",
            "binary_version": "1.1.4-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "fastnetmon",
        "purl": "pkg:deb/ubuntu/fastnetmon@1.1.4-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.1.4-1",
        "1.1.4-1build3",
        "1.1.4-1build4",
        "1.1.4-1build5",
        "1.1.4-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "fastnetmon",
            "binary_version": "1.2.6-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "fastnetmon",
        "purl": "pkg:deb/ubuntu/fastnetmon@1.2.6-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.2.5-1",
        "1.2.6-1",
        "1.2.6-1build1",
        "1.2.6-1build2",
        "1.2.6-1build3",
        "1.2.6-1build4",
        "1.2.6-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "fastnetmon",
            "binary_version": "1.2.8+git20250911-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "fastnetmon",
        "purl": "pkg:deb/ubuntu/fastnetmon@1.2.8+git20250911-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.2.8-1build1",
        "1.2.8-1build2",
        "1.2.8+git20250911-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "fastnetmon",
            "binary_version": "1.2.8+git20250911-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "fastnetmon",
        "purl": "pkg:deb/ubuntu/fastnetmon@1.2.8+git20250911-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.2.8+git20250911-1",
        "1.2.8+git20250911-1build1",
        "1.2.8+git20250911-1build2",
        "1.2.8+git20250911-2",
        "1.2.8+git20250911-2ubuntu0.1~esm1"
      ]
    }
  ],
  "aliases": [],
  "details": "FastNetMon Community Edition through 1.2.9 has out-of-bounds memory access because it incorrectly parses BGP path attributes with the extended length flag set. In src/bgp_protocol.hpp, the parse_raw_bgp_attribute() function correctly identifies when extended_length_bit is set and sets length_of_length_field to 2, but then reads only a single byte for the attribute value length (attribute_value_length = value[2] at line 173). Per RFC 4271 Section 4.3, when the Extended Length bit is set, the Attribute Length field is two octets and the value should be read as a 16-bit big-endian integer from value[2] and value[3]. As a result, any attribute longer than 255 bytes has its length silently truncated to the low byte (e.g., 300 bytes = 0x012C is read as 0x2C = 44 bytes). The remaining 256 bytes are then misinterpreted as subsequent attributes, causing cascading parse failures and potential out-of-bounds memory access.",
  "id": "UBUNTU-CVE-2026-48685",
  "modified": "2026-06-15T18:15:28Z",
  "published": "2026-05-26T16:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-48685"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-48685"
    },
    {
      "type": "REPORT",
      "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48685-bgp-extended-length"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pavel-odintsov/fastnetmon/commit/2bf813b2590b9847308877a65fc72df560dd282f"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pavel-odintsov/fastnetmon"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-48685"
  ]
}



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