Executive Summary

MikroTik RouterBOARD v6.39.2 and v6.40.5 allow an unauthenticated remote attacker to trigger a denial‑of‑service by connecting to TCP port 53 and sending a payload that starts with numerous null bytes, potentially exploiting DNS handling. The flaw can cause the device to crash or become unresponsive, impacting network availability.

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Authoritative CVE Metadata - CVSS Base Score: 7.5 (HIGH) - Published: 2017-12-13T16:29:00.363 - Last Modified: 2026-09-16T21:17:04.613

Original Description: 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.

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