MikroTik RouterOS and Cloud Hosted Router
View CSAF Summary Successful exploitation of this vulnerability could allow attackers to rapidly guess passwords and gain unauthorized system access. The following versions of MikroTik RouterOS and Cloud Hosted Router are affected: RouterOS vers:all/* (CVE-2026-16347) Cloud Hosted Router vers:all/* (CVE-2026-16347) CVSS Vendor Equipment Vulnerabilities v3 8.8 MikroTik MikroTik RouterOS and Cloud Hosted Router Improper Restriction of Excessive Authentication Attempts Background Critical Infrastructure Sectors: Information Technology, Commercial Facilities Countries/Areas Deployed: Worldwide Company Headquarters Location: Latvia Vulnerabilities Expand All + CVE-2026-16347 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. View CVE Details Affected Products MikroTik RouterOS and Cloud Hosted Router Vendor: MikroTik Product Version: MikroTik RouterOS: vers:all/*, MikroTik Cloud Hosted Router: vers:all/* Product Status: known_affected Remediations Mitigation 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. Mitigation Configure the unsuccessful-attempt time range (0.1 to 0.5 seconds) in /ip service for all services, including the API, once available. Mitigation Connect initially from a trusted network (LAN) port only, then conf
CSIRTS triage
- What
- A vulnerability allows attackers to rapidly guess passwords and gain unauthorized system access due to improper authentication handling.
- Who is affected
- Deployments of MikroTik RouterOS and Cloud Hosted Router worldwide.
- Urgency
- Remediation is critical as the vulnerability has a high severity (CVSS 8.8) and could lead to unauthorized access.
- Action
- Implement rate-limiting and account lockout measures, and update to the latest versions.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://www.cisa.gov/news-events/ics-advisories/icsa-26-209-05
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-163470.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 14% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-16347 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
Recent advisories for MikroTik RouterOS and
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- mediumCVE-2026-14227: An API session‑management flaw in products with the MikroTik RouterOS API enabled are vulnerab…nvd · 2026-07-30
- criticalMikroTik RouterOScisa · 2026-07-30
- highCVE-2026-16347: MikroTik RouterOS contains a weakness in its API authentication handling that lacks effective …nvd · 2026-07-28
- highCVE-2026-39042: An issue in MikroTIk (SIA Mikrotikls, Latvia) RouterOS 7.21.x before v.7.21.4 and 7.22.x befor…nvd · 2026-07-13
- criticalexploitedCVE-2018-7445: MikroTik RouterOS Stack-Based Buffer Overflow Vulnerabilitycisa-kev · 2022-09-08
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