CVE-2026-16347

Improper restriction of excessive authentication attempts in MikroTik RouterOS and Cloud Hosted Router

State
Published
Severity
8.7 High
Published
Jul 28, 2026
Updated
Jul 29, 2026
Reserved
Jul 20, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
4.08.7 HighCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:Nicscert
3.18.8 HighCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hicscert

Weaknesses

  • CWE-307 Improper restriction of excessive authentication attempts

Affected Products

ProductVersions
RouterOSMikroTik
  • All versionsAffected
Cloud Hosted RouterMikroTik
  • All versionsAffected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.