FKIE_CVE-2026-67277

Vulnerability from fkie_nvd - Published: 2026-09-05 20:17 - Updated: 2026-09-11 12:52
Severity
8.2 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Summary
RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
References
cvd@cert.plhttps://cert.pl/en/posts/2026/09/mikrotik-routeros-cveThird Party Advisory
cvd@cert.plhttps://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/Mitigation, Third Party Advisory
cvd@cert.plhttps://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802Release Notes
cvd@cert.plhttps://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801Release Notes
cvd@cert.plhttps://forum.mikrotik.com/t/7-24-2-stable-is-released/272800Release Notes
cvd@cert.plhttps://mikrotik.com/supportsec/september-2026-vulnerability/Vendor Advisory
cvd@cert.plhttps://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/Exploit, Third Party Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277US Government Resource
Impacted products
Vendor Product Version
mikrotik routeros *
mikrotik routeros *
mikrotik routeros *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "RouterOS",
          "vendor": "Mikrotik",
          "versions": [
            {
              "lessThan": "7.24.2",
              "status": "affected",
              "version": "7.24",
              "versionType": "custom"
            },
            {
              "lessThan": "7.23.4",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "custom"
            },
            {
              "lessThan": "6.49.21",
              "status": "affected",
              "version": "6.0.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "cvd@cert.pl"
    }
  ],
  "cisaActionDue": "2026-09-13",
  "cisaExploitAdd": "2026-09-10",
  "cisaRequiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA\u2019s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA\u2019s \u201cForensics Triage Requirements\u201d (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset\u0027s internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
  "cisaVulnerabilityName": "MikroTik RouterOS Missing Authentication for Critical Function Vulnerability",
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CFC981EC-B44C-40B5-945B-2283FADEC961",
              "versionEndExcluding": "6.49.21",
              "versionStartIncluding": "6.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "881306AB-32B1-4B5F-96D8-9532D25F7AE4",
              "versionEndExcluding": "7.23.4",
              "versionStartIncluding": "7.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "A41D6B3C-D321-4C61-B3D5-00F8276CB4AC",
              "versionEndExcluding": "7.24.2",
              "versionStartIncluding": "7.24",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "RouterOS accepts a \"related\" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With \"random-data=false\", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel.\n\n\n\nThis issue was fixed in versions:\u00a06.49.21 (Long-term),\u00a07.23.4 (Long-term)\u00a0and\u00a07.24.2 (Stable)"
    }
  ],
  "id": "CVE-2026-67277",
  "lastModified": "2026-09-11T12:52:29.533",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 4.2,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cvd@cert.pl",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-67277",
          "options": [
            {
              "exploitation": "active"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-08T00:00:00+00:00",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-05T20:17:18.120",
  "references": [
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Release Notes"
      ],
      "url": "https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Release Notes"
      ],
      "url": "https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Release Notes"
      ],
      "url": "https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://mikrotik.com/supportsec/september-2026-vulnerability/"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "url": "https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "US Government Resource"
      ],
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277"
    }
  ],
  "sourceIdentifier": "cvd@cert.pl",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-306"
        }
      ],
      "source": "cvd@cert.pl",
      "type": "Secondary"
    }
  ]
}



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