{"id":"CVE-2026-103903","state":"PUBLISHED","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.","publishedAt":"2026-10-12T10:37:23.578Z","updatedAt":"2026-10-13T11:57:50.805Z","severity":{"score":8.7,"label":"High","version":"4.0","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","source":"ENISA"},"assigner":"ENISA","products":["MikroTik RouterOS"],"affected":[{"vendor":"MikroTik","product":"RouterOS","defaultStatus":"affected","versions":[{"version":"7.0.0","status":"affected","lessThan":"7.24.5","versionType":"semver"},{"version":"7.25rc1","status":"unaffected","versionType":"custom"}],"modules":["WinBox authentication / user service"]}],"references":["https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","https://cvd.cert.lv/disclosed/vuln-all-709639748"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/103xxx/CVE-2026-103903.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-103903","state":"PUBLISHED","datePublished":"2026-10-12T10:37:23.578Z","dateUpdated":"2026-10-13T11:57:50.805Z","assignerShortName":"ENISA","assignerOrgId":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","dateReserved":"2026-10-01T14:12:50.876Z"},"containers":{"cna":{"title":"MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation","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'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."}],"affected":[{"vendor":"MikroTik","product":"RouterOS","defaultStatus":"affected","versions":[{"version":"7.0.0","status":"affected","lessThan":"7.24.5","versionType":"semver"},{"version":"7.25rc1","status":"unaffected","versionType":"custom"}],"modules":["WinBox authentication / user service"]}],"references":[{"url":"https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","name":"MikroTik RouterOS 7.24.5 stable release notes","tags":["release-notes"]},{"url":"https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","tags":["release-notes"]},{"url":"https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","tags":["technical-description","third-party-advisory"]},{"url":"https://cvd.cert.lv/disclosed/vuln-all-709639748","tags":["government-resource"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8.7,"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"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":8.8,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863 Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"ENISA","orgId":"a6d3dc9e-0591-4a13-bce7-0f5b31ff6158","dateUpdated":"2026-10-12T10:37:23.578Z"},"workarounds":[{"lang":"en","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.","supportingMedia":[{"type":"text/html","base64":false,"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>"}]}],"solutions":[{"lang":"en","value":"Upgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix.","supportingMedia":[{"type":"text/html","base64":false,"value":"<span>Upgrade to RouterOS 7.24.5 stable, 7.25rc1 testing, or\na later vendor release containing the fix.</span>"}]}],"x_generator":{"engine":"Vulnogram 1.0.5"},"source":{"discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-103903","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-13T03:55:34.306578Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-13T11:57:50.805Z"}}]}}}