High severity · published Oct 29, 2019
CVE-2019-3978
RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and below allow remote unauthenticated attackers to trigger DNS queries via port 8291
7.5
CVSS
10.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)10.3% · higher than 96% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RO
Routeros · Mikrotik
through 6.44.5; through 6.45.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-3978
CVE.org
https://www.cve.org/CVERecord?id=CVE-2019-3978
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
More from Routeros
9.8
CVE-2026-86060
SSH session privilege manipulation via a crafted username in Mikrotik RouterOS
9.8
CVE-2018-7445
MikroTik RouterOS Stack-Based Buffer Overflow Vulnerability
9.1
CVE-2018-14847
MikroTik Router OS Directory Traversal Vulnerability
8.2
CVE-2026-67277
Kernel memory disclosure and denial of service in MikroTik RouterOS btest service
6.5
CVE-2026-67279
SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS