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Vulnerability record · CVE-2019-3978 · published 29 October 2019

CVE-2019-3978: Mikrotik routeros missing authentication for critical function vulnerability

Mikrotik · Routeros

RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and below allow remote unauthenticated attackers to trigger DNS queries via port 8291. The queries are sent from the router to a server of the attacker's choice. The DNS responses are cached by the router, potentially resulting in cache poisoning

7.5 CVSS 3.1 High EPSS 10% · top 4.5% CWE-306 · Missing authentication for critical function
7.5CVSS 3.1 base score, v2 5.0
10%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and below allow remote unauthenticated attackers to trigger DNS queries via port 8291. The queries are sent from the router to a server of the attacker's choice. The DNS responses are cached by the router, potentially resulting in cache poisoning

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/155036/MikroTik-RouterOS-6.45.6-DNS-Cache-Poisoning.html Third Party Advisory
https://www.tenable.com/security/research/tra-2019-46 Third Party Advisory
http://packetstormsecurity.com/files/155036/MikroTik-RouterOS-6.45.6-DNS-Cache-Poisoning.html Third Party Advisory
https://www.tenable.com/security/research/tra-2019-46 Third Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-3978), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.