CVE-2026-16347

Administrative access via concurrent API password guessing

Published Jul 28, 2026 · Updated Jul 28, 2026

Improper login-attempt restriction in MikroTik RouterOS and Cloud Hosted Router allows attackers to guess API credentials. The API authentication path neither meaningfully rate-limits failed logins nor locks accounts or source addresses, while concurrent sessions bypass its per-connection delay. Reachability requires an enabled API service and adjacent-network access; successful guessing grants unauthorized administrative access.

CVSS severity8.7
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper login-attempt restriction in MikroTik RouterOS and Cloud Hosted Router allows attackers to guess API credentials. The API authentication path neither meaningfully rate-limits failed logins nor locks accounts or source addresses, while concurrent sessions bypass its per-connection delay. Reachability requires an enabled API service and adjacent-network access; successful guessing grants unauthorized administrative access.

The record

CVE
CVE-2026-16347
Published
Jul 28, 2026
Updated
Jul 28, 2026
Vendor
MikroTik
Product
RouterOS
Classifications
CWE-307, CAPEC-49, T1110.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=All versions

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

MikroTik · RouterOSversion=All versions
MikroTik · Cloud Hosted Router (CHR)version=All versions

Published CVSS scores

8.7ICS-CERTCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8ICS-CERTCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
CAPEC-49Password Brute Forcing
T1110.001Password Guessing

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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