CVE-2026-16347 (GCVE-0-2026-16347)

Vulnerability from cvelistv5 – Published: 2026-07-28 19:59 – Updated: 2026-07-28 19:59
VLAI
Title
Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router
Summary
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
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.7 (High)
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
CWE
  • CWE-307 - Improper restriction of excessive authentication attempts
Assigner
References
Impacted products
Credits
Andre Santos of União Geek reported this vulnerability to CISA.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "affected",
          "product": "RouterOS",
          "vendor": "MikroTik",
          "versions": [
            {
              "status": "affected",
              "version": "All versions"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Cloud Hosted Router",
          "vendor": "MikroTik",
          "versions": [
            {
              "status": "affected",
              "version": "All versions"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Andre Santos of Uni\u00e3o Geek reported this vulnerability to CISA."
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "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.\u0026nbsp;\u003cbr\u003e"
            }
          ],
          "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "ADJACENT",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-307",
              "description": "CWE-307 Improper restriction of excessive authentication attempts",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-28T19:59:29.927Z",
        "orgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
        "shortName": "icscert"
      },
      "references": [
        {
          "tags": [
            "government-resource"
          ],
          "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-209-05"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router",
      "workarounds": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "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\u003cbr\u003e* Configure the unsuccessful-attempt time range (0.1 to 0.5 seconds) in /ip service for all services, including the API, once available.\n\u003cbr\u003e* Connect initially from a trusted network (LAN) port only, then configure the router per your security requirements.\n\u003cbr\u003e* Restrict/limit access to management services from untrusted networks.\n\u003cbr\u003e* Apply firewall rules to control and restrict access to management services where possible.\n\u003cbr\u003e* Use long, randomly generated passwords rather than weak or default-simple ones, to keep the brute-force search space impractically large.\n\u003cbr\u003e* Keep the default randomly generated device password, or replace it with an equally strong one, since minimum complexity isn\u0027t enforced by default.\n\u003cbr\u003e\n\u003cbr\u003eUsers are encouraged to reach out to MikroTik (https://mikrotik.com/support) for further support.\u0026nbsp;"
            }
          ],
          "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\u0027t enforced by default.\n\n\n\nUsers are encouraged to reach out to MikroTik (https://mikrotik.com/support) for further support."
        }
      ],
      "x_generator": {
        "engine": "Vulnogram 1.0.4"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "7d14cffa-0d7d-4270-9dc0-52cabd5a23a6",
    "assignerShortName": "icscert",
    "cveId": "CVE-2026-16347",
    "datePublished": "2026-07-28T19:59:29.927Z",
    "dateReserved": "2026-07-20T20:41:22.596Z",
    "dateUpdated": "2026-07-28T19:59:29.927Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-16347\",\"sourceIdentifier\":\"ics-cert@hq.dhs.gov\",\"published\":\"2026-07-28T20:17:23.713\",\"lastModified\":\"2026-07-28T20:17:23.713\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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.\"}],\"affected\":[{\"source\":\"ics-cert@hq.dhs.gov\",\"affectedData\":[{\"vendor\":\"MikroTik\",\"product\":\"RouterOS\",\"defaultStatus\":\"affected\",\"versions\":[{\"version\":\"All versions\",\"status\":\"affected\"}]},{\"vendor\":\"MikroTik\",\"product\":\"Cloud Hosted Router\",\"defaultStatus\":\"affected\",\"versions\":[{\"version\":\"All versions\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"ics-cert@hq.dhs.gov\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"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/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\",\"baseScore\":8.7,\"baseSeverity\":\"HIGH\",\"attackVector\":\"ADJACENT\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"HIGH\",\"vulnIntegrityImpact\":\"HIGH\",\"vulnAvailabilityImpact\":\"HIGH\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"ics-cert@hq.dhs.gov\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"ADJACENT_NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"ics-cert@hq.dhs.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-307\"}]}],\"references\":[{\"url\":\"https://www.cisa.gov/news-events/ics-advisories/icsa-26-209-05\",\"source\":\"ics-cert@hq.dhs.gov\"}]}}"
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.