Vulnerability-Lookup

UBUNTU-CVE-2026-48685 (CVE-2026-48685)

Vulnerability from osv_ubuntu – Published: 2026-05-26 16:16 – Updated: 2026-06-15 18:15 – Source website

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

URL

Type

	https://ubuntu.com/security/CVE-2026-48685	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-48685	REPORT
	https://lorikeetsecurity.com/blog/fastnetmon-cve-…	REPORT
	https://github.com/pavel-odintsov/fastnetmon/comm…	REPORT
	https://github.com/pavel-odintsov/fastnetmon	REPORT
	https://github.com/pavel-odintsov/fastnetmon/blob…	REPORT

JSON

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"
  ]
}

CVE-2026-48685 (GCVE-0-2026-48685)

Vulnerability from cvelistv5 – Published: 2026-05-26 00:00 – Updated: 2026-05-26 20:56

Summary

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-26 20:56 UTC

CWE

n/a
CWE-130 - Improper Handling of Length Parameter Inconsistency

Assigner

mitre mitre root

References

3 references

URL	Tags
https://github.com/pavel-odintsov/fastnetmon
https://github.com/pavel-odintsov/fastnetmon/blob…
https://lorikeetsecurity.com/blog/fastnetmon-cve-…

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 6.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-48685",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-26T20:56:09.270143Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-130",
                "description": "CWE-130 Improper Handling of Length Parameter Inconsistency",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-26T20:56:12.251Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-26T15:22:07.299Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/pavel-odintsov/fastnetmon"
        },
        {
          "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.hpp"
        },
        {
          "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48685-bgp-extended-length"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-48685",
    "datePublished": "2026-05-26T00:00:00.000Z",
    "dateReserved": "2026-05-22T00:00:00.000Z",
    "dateUpdated": "2026-05-26T20:56:12.251Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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Nomenclature

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Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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UBUNTU-CVE-2026-48685 (CVE-2026-48685)

CVE-2026-48685 (GCVE-0-2026-48685)

Tags

Sightings

Nomenclature

Related by attack behaviour