{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-37186",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-37186",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2021-09-14T10:47:49.000Z",
    "updatedAt": "2024-08-04T01:16:03.873Z",
    "importedAt": "2026-10-24T01:56:32.228Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": null,
      "summary": "A vulnerability has been identified in LOGO! CMR2020 (All versions < V2.2), LOGO! CMR2040 (All versions < V2.2), SIMATIC RTU3010C (All versions < V4.0.9), SIMATIC RTU3030C (All versions < V4.0.9), SIMATIC RTU3031C (All versions < V4.0.9), SIMATIC RTU3041C (All versions < V4.0.9). The underlying TCP/IP stack does not properly calculate the random numbers used as ISN (Initial Sequence Numbers). An adjacent attacker with network access to the LAN interface could interfere with traffic, spoof the connection and gain access to sensitive information.",
      "affected": [
        {
          "vendor": "Siemens",
          "product": "LOGO! CMR2020",
          "versions": [
            {
              "version": "All versions < V2.2",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "LOGO! CMR2040",
          "versions": [
            {
              "version": "All versions < V2.2",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC RTU3010C",
          "versions": [
            {
              "version": "All versions < V4.0.9",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC RTU3030C",
          "versions": [
            {
              "version": "All versions < V4.0.9",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC RTU3031C",
          "versions": [
            {
              "version": "All versions < V4.0.9",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Siemens",
          "product": "SIMATIC RTU3041C",
          "versions": [
            {
              "version": "All versions < V4.0.9",
              "status": "affected"
            }
          ]
        }
      ]
    }
  }
}