{"schemaVersion":3,"id":"CVE-2026-103903","aliases":[],"status":"published","duplicateOf":null,"title":null,"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.","dates":{"published":"2026-10-12T10:37:23.578Z","modified":"2026-10-13T11:57:50.805Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.8,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"NVD","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","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","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","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","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","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","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","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00415,"percentile":0.3465,"severity":"low","asOf":"2026-10-21T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-13T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00415,"percentile":0.3465}],"last30":[{"date":"2026-10-13T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00415,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00415,"percentile":0.3465}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-863","name":"Incorrect Authorization","description":"The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.","type":"weakness","status":"Incomplete","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/863.html"}],"affected":[{"vendor":"mikrotik","product":"routeros","name":"RouterOS","label":"routeros","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 7.0.0, < 7.24.5","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 7.0.0, < 7.24.5","eol":{"isEol":null,"eolDate":null,"matchMethod":"cpe","cycle":null,"product":{"name":"routeros","label":"RouterOS","category":"os"}},"hubHref":"/vendor/mikrotik/routeros"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","label":"br2sec.com/lv/resursi/2026-routeros-winbox-auth-bypass/","hostname":"br2sec.com","tags":["Technical Description","Third Party Advisory"]},{"url":"https://cvd.cert.lv/disclosed/vuln-all-709639748","label":"cvd.cert.lv/disclosed/vuln-all-709639748","hostname":"cvd.cert.lv","tags":["Government Resource"]},{"url":"https://forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","label":"forum.mikrotik.com/t/7-25rc1-testing-is-released/27352","hostname":"forum.mikrotik.com","tags":["Release Notes"]},{"url":"https://mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","label":"mikrotik.com/download/changelogs?channelFilter=stable&versionFilter=7.24.5","hostname":"mikrotik.com","tags":["Release Notes"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-12T10:37:23.578Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-13T11:57:50.805Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T18:38:25.618Z","stale":false,"partial":false}}