Vulnerability-Lookup

GHSA-CQ44-X9VF-FPQG

Vulnerability from github – Published: 2026-09-05 21:31 – Updated: 2026-09-05 21:31

Details

MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation.

This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

Severity

6.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-67278"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-05T20:17:18Z",
    "severity": "MODERATE"
  },
  "details": "MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root\u2019s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation.\n\nThis issue was fixed in versions:\u00a06.49.21 (Long-term),\u00a07.23.4 (Long-term)\u00a0and\u00a07.24.2 (Stable)",
  "id": "GHSA-cq44-x9vf-fpqg",
  "modified": "2026-09-05T21:31:20Z",
  "published": "2026-09-05T21:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67278"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited"
    },
    {
      "type": "WEB",
      "url": "https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802"
    },
    {
      "type": "WEB",
      "url": "https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801"
    },
    {
      "type": "WEB",
      "url": "https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800"
    },
    {
      "type": "WEB",
      "url": "https://mikrotik.com/supportsec/september-2026-vulnerability"
    },
    {
      "type": "WEB",
      "url": "https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-67278 (GCVE-0-2026-67278)

Vulnerability from cvelistv5 – Published: 2026-09-05 20:00 – Updated: 2026-09-05 20:40

Title

TLS server impersonation possible in Mikrotik RouterOS

Summary

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CWE

CWE-347 - Improper verification of cryptographic signature

Assigner

CERT-PL ENISA root

References

7 references

URL	Tags
https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve	third-party-advisory
https://cert.pl/en/posts/2026/09/vulnerabilities-…	technical-description
https://npratley.net/reversing-mikrotiks-silent-p…	exploit
https://mikrotik.com/supportsec/september-2026-vu…	vendor-advisory
https://forum.mikrotik.com/t/6-49-21-long-term-is…	release-notes
https://forum.mikrotik.com/t/7-23-4-long-term-is-…	release-notes
https://forum.mikrotik.com/t/7-24-2-stable-is-rel…	release-notes

Impacted products

1 product

Vendor	Product	Version
Mikrotik	RouterOS	Affected: 7.24 , < 7.24.2 (custom) Affected: 7.0.0 , < 7.23.4 (custom) Affected: 6.0.0 , < 6.49.21 (custom) cpe:2.3:a:mikrotik:routeros::::::::

Credits

Sławomir Rozbicki (CERT.PL)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:mikrotik:routeros:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.25.1",
                  "versionStartIncluding": "0.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "OR"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "S\u0142awomir Rozbicki (CERT.PL)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cdiv\u003e\u003cspan\u003eMikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root\u2019s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation.\u003c/span\u003e\u003c/div\u003e\u003cdiv\u003eThis issue was fixed in versions:\u0026nbsp;6.49.21 (Long-term),\u0026nbsp;7.23.4 (Long-term)\u0026nbsp;and\u0026nbsp;7.24.2 (Stable)\u003c/div\u003e"
            }
          ],
          "value": "MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root\u2019s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation.\n\nThis issue was fixed in versions:\u00a06.49.21 (Long-term),\u00a07.23.4 (Long-term)\u00a0and\u00a07.24.2 (Stable)"
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "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:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
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          "descriptions": [
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              "description": "CWE-347 Improper verification of cryptographic signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-05T20:40:10.587Z",
        "orgId": "4bb8329e-dd38-46c1-aafb-9bf32bcb93c6",
        "shortName": "CERT-PL"
      },
      "references": [
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/"
        },
        {
          "tags": [
            "exploit"
          ],
          "url": "https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mikrotik.com/supportsec/september-2026-vulnerability/"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800"
        }
      ],
      "source": {
        "discovery": "INTERNAL"
      },
      "title": "TLS server impersonation possible in Mikrotik RouterOS",
      "x_generator": {
        "engine": "Vulnogram 1.0.3"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "4bb8329e-dd38-46c1-aafb-9bf32bcb93c6",
    "assignerShortName": "CERT-PL",
    "cveId": "CVE-2026-67278",
    "datePublished": "2026-09-05T20:00:57.258Z",
    "dateReserved": "2026-07-29T11:59:30.538Z",
    "dateUpdated": "2026-09-05T20:40:10.587Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Action not permitted

GHSA-CQ44-X9VF-FPQG

CVE-2026-67278 (GCVE-0-2026-67278)

Tags

Sightings

Nomenclature