Vulnerability-Lookup

FKIE_CVE-2026-103903

Vulnerability from fkie_nvd - Published: 2026-10-12 11:17 - Updated: 2026-10-13 12:17

Severity

8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

An incorrect authorization vulnerability in the WinBox authentication flow of MikroTik RouterOS allows a remote authenticated attacker with credentials for a low-privilege account permitted to use WinBox to obtain the authorization policy of a different existing account. The stage-one EC-SRP challenge and proof are verified using the attacker's account, while the independently supplied stage-two username is used to install the target account's privileges. By specifying a higher-privilege account such as admin, a low-privilege user can obtain a full administrative session without knowing the target account's password and can use that session to increase the privileges of the attacker's own account.

References

	URL	Tags
	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158	https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/
	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158	https://cvd.cert.lv/disclosed/vuln-all-709639748
	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158	https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352
	a6d3dc9e-0591-4a13-bce7-0f5b31ff6158	https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "affected",
          "modules": [
            "WinBox authentication / user service"
          ],
          "product": "RouterOS",
          "vendor": "MikroTik",
          "versions": [
            {
              "lessThan": "7.24.5",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.25rc1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An incorrect authorization vulnerability in the WinBox\nauthentication flow of MikroTik RouterOS allows a remote authenticated attacker\nwith credentials for a low-privilege account permitted to use WinBox to obtain\nthe authorization policy of a different existing account. The stage-one EC-SRP\nchallenge and proof are verified using the attacker\u0027s account, while the\nindependently supplied stage-two username is used to install the target\naccount\u0027s privileges. By specifying a higher-privilege account such as admin, a\nlow-privilege user can obtain a full administrative session without knowing the\ntarget account\u0027s password and can use that session to increase the privileges\nof the attacker\u0027s own account."
    }
  ],
  "id": "CVE-2026-103903",
  "lastModified": "2026-10-13T12:17:11.280",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "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": "LOW",
          "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:L/UI:N/VC:H/VI:H/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": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-103903",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-13T03:55:34.306578Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-12T11:17:09.517",
  "references": [
    {
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
      "url": "https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/"
    },
    {
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
      "url": "https://cvd.cert.lv/disclosed/vuln-all-709639748"
    },
    {
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
      "url": "https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352"
    },
    {
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
      "url": "https://mikrotik.com/download/changelogs?channelFilter=stable\u0026versionFilter=7.24.5"
    }
  ],
  "sourceIdentifier": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "a6d3dc9e-0591-4a13-bce7-0f5b31ff6158",
      "type": "Secondary"
    }
  ]
}

CVE-2026-103903 (GCVE-0-2026-103903)

Vulnerability from cvelistv5 – Published: 2026-10-12 10:37 – Updated: 2026-10-13 11:57

Title

MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation

Summary

Severity

8.7 (High)


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

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-13 03:55 UTC

CWE

CWE-863 - Incorrect Authorization

Assigner

ENISA CNA under the ENISA root

CNA scorecard B 78/100 over 37 records in the last 180 days details

References

4 references

URL	Tags
https://mikrotik.com/download/changelogs?channelF…	release-notes
https://forum.mikrotik.com/t/7-25rc1-testing-is-r…	release-notes
https://br2sec.com/lv/resursi/2026-routeros-winbo…	technical-descriptionthird-party-advisory
https://cvd.cert.lv/disclosed/vuln-all-709639748	government-resource

Impacted products

1 product

Vendor	Product	Version
MikroTik	RouterOS	Affected: 7.0.0 , < 7.24.5 (semver) Unaffected: 7.25rc1 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-103903",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-13T03:55:34.306578Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-13T11:57:50.805Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "affected",
          "modules": [
            "WinBox authentication / user service"
          ],
          "product": "RouterOS",
          "vendor": "MikroTik",
          "versions": [
            {
              "lessThan": "7.24.5",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.25rc1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cspan\u003eAn incorrect authorization vulnerability in the WinBox\nauthentication flow of MikroTik RouterOS allows a remote authenticated attacker\nwith credentials for a low-privilege account permitted to use WinBox to obtain\nthe authorization policy of a different existing account. The stage-one EC-SRP\nchallenge and proof are verified using the attacker\u0027s account, while the\nindependently supplied stage-two username is used to install the target\naccount\u0027s privileges. By specifying a higher-privilege account such as admin, a\nlow-privilege user can obtain a full administrative session without knowing the\ntarget account\u0027s password and can use that session to increase the privileges\nof the attacker\u0027s own account.\u003c/span\u003e"
            }
          ],
          "value": "An incorrect authorization vulnerability in the WinBox\nauthentication flow of MikroTik RouterOS allows a remote authenticated attacker\nwith credentials for a low-privilege account permitted to use WinBox to obtain\nthe authorization policy of a different existing account. The stage-one EC-SRP\nchallenge and proof are verified using the attacker\u0027s account, while the\nindependently supplied stage-two username is used to install the target\naccount\u0027s privileges. By specifying a higher-privilege account such as admin, a\nlow-privilege user can obtain a full administrative session without knowing the\ntarget account\u0027s password and can use that session to increase the privileges\nof the attacker\u0027s own account."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "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:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
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          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
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            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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      "problemTypes": [
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        },
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              "value": "\u003cspan\u003eUpgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix.\u003c/span\u003e"
            }
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      "source": {
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      "title": "MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation",
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            }
          ],
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    "assignerShortName": "ENISA",
    "cveId": "CVE-2026-103903",
    "datePublished": "2026-10-12T10:37:23.578Z",
    "dateReserved": "2026-10-01T14:12:50.876Z",
    "dateUpdated": "2026-10-13T11:57:50.805Z",
    "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.

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.
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FKIE_CVE-2026-103903

CVE-2026-103903 (GCVE-0-2026-103903)

Tags

Sightings

Nomenclature

Related by attack behaviour