{
  "crds_version": "0.1",
  "kind": "base",
  "id": "crds:cve-2024-40891",
  "revision": 1,
  "title": "Zyxel DSL modems — command injection over telnet",
  "summary": "The affected Zyxel modem firmware (VMG4325-B10A) runs operating system commands out of its management commands over telnet, for anyone already signed in. The device line is unsupported.",
  "source_type": "cve",
  "severity": "high",
  "cvss": {
    "score": 8.8,
    "vector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
    "version": "3.1"
  },
  "epss": 0.21536,
  "exploitation": {
    "known_exploited": true,
    "exploit_available": false,
    "attack_complexity": "low",
    "kev_added": "2025-02-11",
    "prerequisites": "A valid login on the device's telnet service."
  },
  "mitre_attack": [
    "T1059"
  ],
  "kill_chain": "execution",
  "recommended_action": "Replace these modems — the line is unsupported and no fix is coming; until then stop the telnet service and keep them off routable networks.",
  "confidence": "high",
  "provenance": [
    {
      "fields": [
        "cvss",
        "exploitation.attack_complexity",
        "exploitation.exploit_available",
        "references",
        "published_at"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2024-40891",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "exploitation.known_exploited",
        "exploitation.kev_added"
      ],
      "source": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "epss"
      ],
      "source": "https://api.first.org/data/v1/epss?cve=CVE-2024-40891",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "scrty-crds-pipeline/0.1"
    },
    {
      "fields": [
        "title",
        "summary",
        "severity",
        "remediation",
        "mitre_attack",
        "kill_chain",
        "recommended_action",
        "confidence",
        "tags",
        "exploitation.prerequisites"
      ],
      "source": "https://nvd.nist.gov/vuln/detail/CVE-2024-40891",
      "retrieved_at": "2026-09-24T12:03:01.274Z",
      "confidence": "high",
      "extractor": "claude-code"
    }
  ],
  "references": [
    {
      "type": "cve",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-40891",
      "label": "NVD record"
    },
    {
      "type": "cisa",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "label": "CISA Known Exploited Vulnerabilities catalog"
    },
    {
      "type": "vendor_advisory",
      "url": "https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-command-injection-and-insecure-default-credentials-vulnerabilities-in-certain-legacy-dsl-cpe-02-04-2025"
    }
  ],
  "published_at": "2025-02-04T10:15:08.920Z",
  "issued_at": "2026-09-24T12:03:01.274Z",
  "tags": [
    "zyxel",
    "dsl-modem",
    "command-injection",
    "end-of-life",
    "kev"
  ]
}