7.5High

Mikrotik Routerboard

CVE-2017-17537

MikroTik RouterBOARD v6.39.2 and v6.40.5 allows an unauthenticated remote attacker to cause a denial of service by connecting to TCP port 53 and sending data that begins with many '\0' characters, possibly related to DNS.

What this means for your business

  • It affects Mikrotik Routerboard. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.

What to do

  1. 1Check whether your company or your suppliers run Mikrotik Routerboard, and which version. The affected versions are listed further down this page.
  2. 2If you do, follow the vendor's guidance. No patch reference has been published yet.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Scoring

CVSS
7.5 (v3.0)
Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-20
Assigned by
cve@mitre.org

Dates

Published
2017-12-13
Last modified
2026-09-16
Sources
NVD

Affected products

  • Mikrotik Routerboard6.39.2, 6.40.5, all versions

As listed in the NVD configuration data. Not a statement about your estate.

References