{"api_version":"1","generated_at":"2026-10-25T03:51:47+00:00","cve":"CVE-2026-103903","urls":{"html":"https://cve.report/CVE-2026-103903","api":"https://cve.report/api/cve/CVE-2026-103903.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-103903","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-103903"},"summary":{"title":"MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation","description":"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's account, while the\nindependently supplied stage-two username is used to install the target\naccount's 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's password and can use that session to increase the privileges\nof the attacker's own account.","state":"PUBLISHED","assigner":"ENISA","published_at":"2026-10-12 11:17:09","updated_at":"2026-10-16 17:25:57"},"problem_types":["CWE-863","CWE-863 CWE-863 Incorrect Authorization"],"metrics":[{"version":"4.0","source":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","type":"Secondary","score":"8.7","severity":"HIGH","vector":"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","data":{"version":"4.0","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","baseScore":8.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"8.7","severity":"HIGH","vector":"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","data":{"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"}},{"version":"3.1","source":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","type":"Secondary","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"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"}}],"references":[{"url":"https://cvd.cert.lv/disclosed/vuln-all-709639748","name":"https://cvd.cert.lv/disclosed/vuln-all-709639748","refsource":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","name":"https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","refsource":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","name":"https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","refsource":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","name":"https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","refsource":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-103903","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103903","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"MikroTik","product":"RouterOS","version":"affected 7.0.0 7.24.5 semver","platforms":[]},{"source":"CNA","vendor":"MikroTik","product":"RouterOS","version":"unaffected 7.25rc1 custom","platforms":[]}],"timeline":[],"solutions":[{"source":"CNA","title":"","value":"Upgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix.","time":"","lang":"en"}],"workarounds":[{"source":"CNA","title":"","value":"Until upgrade, restrict the WinBox service to trusted\nmanagement addresses, remove the winbox policy from low-privilege accounts, or\ndisable WinBox. These measures reduce reachability but do not replace the fix.","time":"","lang":"en"}],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"103903","cve":"CVE-2026-103903","epss":"0.004150000","percentile":"0.342870000","score_date":"2026-10-16","updated_at":"2026-10-17 00:14:16"},"legacy_qids":[]},"source_records":{"cve_program":{"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":"<span>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's account, while the\nindependently supplied stage-two username is used to install the target\naccount's 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's password and can use that session to increase the privileges\nof the attacker's own account.</span>"}],"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's account, while the\nindependently supplied stage-two username is used to install the target\naccount's 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's password and can use that session to increase the privileges\nof the attacker's 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"}]},{"cvssV3_1":{"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"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","description":"CWE-863 Incorrect Authorization","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-12T10:37:23.578Z","orgId":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","shortName":"ENISA"},"references":[{"name":"MikroTik RouterOS 7.24.5 stable release notes","tags":["release-notes"],"url":"https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5"},{"tags":["release-notes"],"url":"https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352"},{"tags":["technical-description","third-party-advisory"],"url":"https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/"},{"tags":["government-resource"],"url":"https://cvd.cert.lv/disclosed/vuln-all-709639748"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<span>Upgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix.</span>"}],"value":"Upgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix."}],"source":{"discovery":"UNKNOWN"},"title":"MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation","workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<span>Until upgrade, restrict the WinBox service to trusted\nmanagement addresses, remove the winbox policy from low-privilege accounts, or\ndisable WinBox. These measures reduce reachability but do not replace the fix.</span>"}],"value":"Until upgrade, restrict the WinBox service to trusted\nmanagement addresses, remove the winbox policy from low-privilege accounts, or\ndisable WinBox. These measures reduce reachability but do not replace the fix."}],"x_generator":{"engine":"Vulnogram 1.0.5"}}},"cveMetadata":{"assignerOrgId":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","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"},"nvd":{"publishedDate":"2026-10-12 11:17:09","lastModifiedDate":"2026-10-16 17:25:57","problem_types":["CWE-863","CWE-863 CWE-863 Incorrect Authorization"],"metrics":{"cvssMetricV40":[{"source":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","type":"Secondary","cvssData":{"version":"4.0","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","baseScore":8.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":5.9}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-13T03:55:34.306578Z","id":"CVE-2026-103903","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"103903","Ordinal":"1","Title":"MikroTik RouterOS WinBox split-principal authentication bypass a","CVE":"CVE-2026-103903","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"103903","Ordinal":"1","NoteData":"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's account, while the\nindependently supplied stage-two username is used to install the target\naccount's 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's password and can use that session to increase the privileges\nof the attacker's own account.","Type":"Description","Title":"MikroTik RouterOS WinBox split-principal authentication bypass a"}]}}}