{"id":"CVE-2026-16347","aliases":["EUVD-2026-50017","GHSA-8v62-p5rj-72x6"],"status":"published","title":"Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router","description":"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.","severity":{"version":"4.0","score":8.7,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00388,"percentile":0.33194,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-307"],"published":"2026-07-28T19:59:29Z","modified":"2026-07-30T14:12:18Z","products":[{"vendor":"mikrotik","product":"cloud hosted router"},{"vendor":"mikrotik","product":"routeros"}],"references":[{"url":"https://www.cisa.gov/news-events/ics-advisories/icsa-26-209-05","tags":["government-resource"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16347"},{"url":"https://github.com/advisories/GHSA-8v62-p5rj-72x6"}],"sources":{"cve":[{"id":"CVE-2026-16347","title":"Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router","description":"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.","status":"published","published":"2026-07-28T19:59:29.927Z","modified":"2026-07-29T13:57:56.713Z","cvss":[{"version":"4.0","score":8.7,"vector":"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","level":"high","assessor":"cna"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-307"],"updated_at":"2026-11-02T14:20:11.24076Z"}],"euvd":[{"id":"EUVD-2026-50017","description":"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.","status":"published","published":"2026-07-28T19:59:29Z","modified":"2026-07-29T13:57:56Z","cvss":[{"version":"4.0","score":8.7,"vector":"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","level":"high"}],"updated_at":"2026-11-02T18:02:30.152277Z"}],"ghsa":[{"id":"GHSA-8v62-p5rj-72x6","title":"MikroTik RouterOS contains a weakness in its API authentication handling that lacks effective...","description":"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.","status":"published","published":"2026-07-28T21:31:33Z","modified":"2026-07-28T21:31:39Z","cvss":[{"version":"4.0","score":8.7,"vector":"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/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","level":"high"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-307"],"updated_at":"2026-11-02T15:09:53.70861Z"}],"nvd":[{"id":"CVE-2026-16347","description":"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.","status":"published","published":"2026-07-28T20:17:23.713Z","modified":"2026-07-30T14:12:18.697Z","cvss":[{"version":"4.0","score":8.7,"vector":"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/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","level":"high","assessor":"secondary"},{"version":"3.1","score":8.8,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-307"],"updated_at":"2026-11-02T14:12:33.249634Z"}]}}