{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-16347","assignerOrgId":"7d14cffa-0d7d-4270-9dc0-52cabd5a23a6","state":"PUBLISHED","assignerShortName":"icscert","dateReserved":"2026-07-20T20:41:22.596Z","datePublished":"2026-07-28T19:59:29.927Z","dateUpdated":"2026-07-29T13:57:56.713Z"},"containers":{"cna":{"providerMetadata":{"orgId":"7d14cffa-0d7d-4270-9dc0-52cabd5a23a6","shortName":"icscert","dateUpdated":"2026-07-28T19:59:29.927Z"},"title":"Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-307","description":"CWE-307 Improper restriction of excessive authentication attempts","type":"CWE"}]}],"affected":[{"vendor":"MikroTik","product":"RouterOS","versions":[{"status":"affected","version":"All versions"}],"defaultStatus":"affected"},{"vendor":"MikroTik","product":"Cloud Hosted Router","versions":[{"status":"affected","version":"All versions"}],"defaultStatus":"affected"}],"descriptions":[{"lang":"en","value":"MikroTik RouterOS contains a weakness in its API authentication handling that lacks effective safeguards against excessive login attempts. The system does not enforce meaningful rate-limiting, account lockout, or source-based restrictions, allowing repeated authentication failures to proceed without defensive response. In some versions, a fixed per-connection delay is present, but it can be bypassed through concurrent sessions, resulting in continued high-volume attempts. This deficiency increases the risk that an attacker could eventually obtain valid credentials and gain unauthorized access to administrative services.","supportingMedia":[{"type":"text/html","base64":false,"value":"MikroTik RouterOS contains a weakness in its API authentication handling that lacks effective safeguards against excessive login attempts. The system does not enforce meaningful rate-limiting, account lockout, or source-based restrictions, allowing repeated authentication failures to proceed without defensive response. In some versions, a fixed per-connection delay is present, but it can be bypassed through concurrent sessions, resulting in continued high-volume attempts. This deficiency increases the risk that an attacker could eventually obtain valid credentials and gain unauthorized access to administrative services.&nbsp;<br>"}]}],"references":[{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-26-209-05","tags":["government-resource"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseSeverity":"HIGH","baseScore":8.8,"vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"ADJACENT","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","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:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"workarounds":[{"lang":"en","value":"No fix is currently available from MikroTik. Until a fix is available, MikroTik recommends that users adopt the following mitigations: Use a strong VPN or other additional protection layer if the API is exposed to public networks.\n\n* Configure the unsuccessful-attempt time range (0.1 to 0.5 seconds) in /ip service for all services, including the API, once available.\n\n* Connect initially from a trusted network (LAN) port only, then configure the router per your security requirements.\n\n* Restrict/limit access to management services from untrusted networks.\n\n* Apply firewall rules to control and restrict access to management services where possible.\n\n* Use long, randomly generated passwords rather than weak or default-simple ones, to keep the brute-force search space impractically large.\n\n* Keep the default randomly generated device password, or replace it with an equally strong one, since minimum complexity isn't enforced by default.\n\n\n\nUsers are encouraged to reach out to MikroTik (https://mikrotik.com/support) for further support.","supportingMedia":[{"type":"text/html","base64":false,"value":"No fix is currently available from MikroTik. Until a fix is available, MikroTik recommends that users adopt the following mitigations: Use a strong VPN or other additional protection layer if the API is exposed to public networks.\n<br>* Configure the unsuccessful-attempt time range (0.1 to 0.5 seconds) in /ip service for all services, including the API, once available.\n<br>* Connect initially from a trusted network (LAN) port only, then configure the router per your security requirements.\n<br>* Restrict/limit access to management services from untrusted networks.\n<br>* Apply firewall rules to control and restrict access to management services where possible.\n<br>* Use long, randomly generated passwords rather than weak or default-simple ones, to keep the brute-force search space impractically large.\n<br>* Keep the default randomly generated device password, or replace it with an equally strong one, since minimum complexity isn't enforced by default.\n<br>\n<br>Users are encouraged to reach out to MikroTik (https://mikrotik.com/support) for further support.&nbsp;"}]}],"credits":[{"lang":"en","value":"Andre Santos of União Geek reported this vulnerability to CISA.","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.4"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-29T13:57:29.902200Z","id":"CVE-2026-16347","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-29T13:57:56.713Z"}}]}}