{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89020","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-09-10T16:23:54.471Z","datePublished":"2026-09-14T18:02:58.553Z","dateUpdated":"2026-11-06T19:25:15.011Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-11-06T19:25:15.011Z"},"title":"MikroTik RouterOS Stack Buffer Overflow via TFTP URL Path Leading to Privilege Escalation","descriptions":[{"lang":"en","value":"MikroTik RouterOS before 7.23.4 (long-term) and 7.24.2 (stable) contains a stack-based buffer overflow vulnerability in the mtget binary's TFTP RRQ builder function that allows authenticated users to crash the mtget worker process by supplying a URL path of 507 bytes or more to the /tool fetch command; the first write outside the 528-byte buffer occurs at 505 bytes. Attackers can trigger the overflow by issuing a fetch command with a crafted tftp:// URL path, which causes an unbounded rep movsb instruction to overwrite saved registers at a deterministic offset, crashing the process without requiring a reachable TFTP server or elevated privileges beyond read-only group membership. On older RouterOS versions, this overflow is not limited to crashing the process: the deterministic overwrite of saved registers is exploitable to achieve persistent privilege escalation on the device. On versions with intact exploit mitigations, the impact is limited to a crash of the mtget worker process."}],"datePublic":"2026-09-03T00:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","description":"Stack-based Buffer Overflow","cweId":"CWE-121","type":"CWE"}]}],"affected":[{"defaultStatus":"unknown","vendor":"MikroTik","product":"RouterOS","versions":[{"status":"affected","version":"6.0.0","versionType":"semver","lessThan":"6.49.21"},{"status":"affected","version":"7.0.0","versionType":"semver","lessThan":"7.23.4"},{"status":"affected","version":"7.24.0","versionType":"semver","lessThan":"7.24.2"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0.0","versionEndExcluding":"6.49.21"},{"vulnerable":true,"criteria":"cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.0","versionEndExcluding":"7.23.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*","versionStartIncluding":"7.24.0","versionEndExcluding":"7.24.2"}]}]}],"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":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","version":"3.1","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"}}],"references":[{"url":"https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800","name":"7.24.2 Release Notes","tags":["patch","release-notes"]},{"url":"https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801","tags":["release-notes","patch"],"name":"7.23.4 Release Notes"},{"url":"https://www.vulncheck.com/advisories/mikrotik-routeros-stack-buffer-overflow-via-tftp-url-path","tags":["third-party-advisory"]},{"url":"https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802","name":"6.49.21 Release Notes","tags":["release-notes","patch"]},{"url":"https://mikrotik.com/supportsec/cve-2026-89020/","name":"MikroTik Security Advisory","tags":["vendor-advisory"]},{"url":"https://gitlab.com/sys65535/CVE-2026-89020-privesc-research","name":"Researcher Disclosure","tags":["technical-description","exploit"]}],"credits":[{"lang":"en","value":"Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc.","type":"finder"},{"lang":"en","value":"Cristiano Maranci","type":"finder"},{"lang":"en","value":"Davide Turaccio","type":"finder"}],"x_generator":{"engine":"vulncheck"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T16:07:48.174278Z","id":"CVE-2026-89020","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-16T16:07:59.845Z"}}]}}