{
  "document": {
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "tlp": {
        "label": "WHITE"
      }
    },
    "lang": "nl",
    "notes": [
      {
        "category": "legal_disclaimer",
        "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this page to enhance access to its information and security advisories. The use of this security advisory is subject to the following terms and conditions:\n\n    NCSC-NL makes every reasonable effort to ensure that the content of this page is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or continuous keeping up-to-date. The information contained in this security advisory is intended solely for the purpose of providing general information to professional users. No rights can be derived from the information provided therein.\n\n    NCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of this security advisory. This includes damage resulting from the inaccuracy of incompleteness of the information contained in the advisory.\n    This security advisory is subject to Dutch law. All disputes related to or arising from the use of this advisory will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
      },
      {
        "category": "description",
        "text": "Beveiligingsonderzoekers hebben een een kwetsbaarheid aangetroffen in Inetutils telnetd (versie 2.7). Deze kwetsbaarheid is volgens de onderzoekers al aanwezig sinds versie 1.9.3 die uit is gekomen in 2015.",
        "title": "Feiten"
      },
      {
        "category": "description",
        "text": "De kwetsbaarheid bevindt zich in de manier waarop de telnetd-service omgaat met de USER-omgeving variabele. Door deze variabele in te stellen op \u0027-f root\u0027, kunnen kwaadwillenden authenticatie omzeilen en rootrechten bemachtigen. Dit is een ernstig risico voor de systeemintegriteit.\n\nDeze kwetsbaarheid is zeer eenvoudig uit te buiten en exploitcode hiervoor is publiek beschikbaar. Het NCSC verwacht dan ook dat er bij publiek toegankelijke telnet servers op korte termijn misbruik van deze kwetsbaarheid plaats zal vinden.",
        "title": "Interpretaties"
      },
      {
        "category": "description",
        "text": "Het NCSC adviseert om managementinterfaces zoals Telnet niet aan het internet te koppelen, maar enkel op aparte managementnetwerken beschikbaar te stellen. Dit beperkt het aanvalsoppervlak aanzienlijk. Daarnaast adviseert het NCSC om IP-allowlisting toe te passen en de Telnet-interface enkel voor vertrouwde clients beschikbaar te stellen.\n\nEr zijn patches beschikbaar om de kwetsbaarheid te verhelpen. Deze moeten echter in de packages van de diverse distributies verwerkt worden voordat ze door te voeren zijn. Tot die tijd zijn de patches slechts door te voeren door deze handigmatig in de code (in telnetd/utility.c) aan te passen en vervolgens zelfstandig te compileren.\n\nZie bijgevoegde referenties voor meer informatie.",
        "title": "Oplossingen"
      },
      {
        "category": "general",
        "text": "high",
        "title": "Kans"
      },
      {
        "category": "general",
        "text": "high",
        "title": "Schade"
      },
      {
        "category": "general",
        "text": "Improper Neutralization of Argument Delimiters in a Command (\u0027Argument Injection\u0027)",
        "title": "CWE-88"
      }
    ],
    "publisher": {
      "category": "coordinator",
      "contact_details": "cert@ncsc.nl",
      "name": "Nationaal Cyber Security Centrum",
      "namespace": "https://www.ncsc.nl/"
    },
    "references": [
      {
        "category": "external",
        "summary": "Reference",
        "url": "https://codeberg.org/inetutils/inetutils/commit/ccba9f748aa8d50a38d7748e2e60362edd6a32cc"
      },
      {
        "category": "external",
        "summary": "Reference",
        "url": "https://codeberg.org/inetutils/inetutils/commit/fd702c02497b2f398e739e3119bed0b23dd7aa7b"
      },
      {
        "category": "external",
        "summary": "Reference",
        "url": "https://seclists.org/oss-sec/2026/q1/89"
      },
      {
        "category": "external",
        "summary": "Reference",
        "url": "https://www.gnu.org/software/inetutils/"
      }
    ],
    "title": "Kwetsbaarheid verholpen in GNU Inetutils telnetd",
    "tracking": {
      "current_release_date": "2026-01-21T14:15:46.424529Z",
      "generator": {
        "date": "2025-08-04T16:30:00Z",
        "engine": {
          "name": "V.A.",
          "version": "1.3"
        }
      },
      "id": "NCSC-2026-0033",
      "initial_release_date": "2026-01-21T14:15:46.424529Z",
      "revision_history": [
        {
          "date": "2026-01-21T14:15:46.424529Z",
          "number": "1.0.0",
          "summary": "Initiele versie"
        }
      ],
      "status": "final",
      "version": "1.0.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:unknown/*",
                "product": {
                  "name": "vers:unknown/*",
                  "product_id": "CSAFPID-1"
                }
              }
            ],
            "category": "product_name",
            "name": "InetUtils"
          }
        ],
        "category": "vendor",
        "name": "GNU"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-24061",
      "cwe": {
        "id": "CWE-88",
        "name": "Improper Neutralization of Argument Delimiters in a Command (\u0027Argument Injection\u0027)"
      },
      "notes": [
        {
          "category": "other",
          "text": "Improper Neutralization of Argument Delimiters in a Command (\u0027Argument Injection\u0027)",
          "title": "CWE-88"
        },
        {
          "category": "description",
          "text": "The GNU Inetutils telnetd version 2.7 is susceptible to a remote authentication bypass due to the manipulation of the USER environment variable to \u0027-f root\u0027.",
          "title": "Summary"
        },
        {
          "category": "general",
          "text": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
          "title": "CVSSV4"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-24061 | NCSC-NL Website",
          "url": "https://vulnerabilities.ncsc.nl/csaf/v2/2026/cve-2026-24061.json"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-1"
          ]
        }
      ],
      "title": "CVE-2026-24061"
    }
  ]
}