How severe is CVE-2019-3978?

CVE-2019-3978 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2019-3978 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-3978?

CVE-2019-3978 primarily affects Mikrotik Routeros. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-3978?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-3978 published?

CVE-2019-3978 was published on 2019-10-29 and last updated on 2026-06-17.

CVE-2019-3978

CVE-2019-3978 is a high-severity vulnerability in Mikrotik Routeros with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 10% places it in the 95th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-306.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 10% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Mikrotik Routeros
Published: 2019-10-29
Last modified: 2026-06-17

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

Frequently asked questions

What is 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. 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
How severe is CVE-2019-3978?: CVE-2019-3978 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2019-3978 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 10% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-3978?: CVE-2019-3978 primarily affects Mikrotik Routeros. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-3978?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-3978 published?: CVE-2019-3978 was published on 2019-10-29 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:mikrotik:routeros:*:*:*:*:ltr:*:*:*
cpe:2.3:o:mikrotik:routeros:*:*:*:*:-:*:*:*

More vulnerabilities in Mikrotik Routeros

CVE-2017-20149 — Critical (CVSS 9.8): The Mikrotik RouterOS web server allows memory corruption in releases before Stable 6.38.5 and Long-term 6.37.5, aka…
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CVE-2018-7445 — Critical (CVSS 9.8): A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS session request messages.…
CVE-2023-30799 — Critical (CVSS 9.1): MikroTik RouterOS stable before 6.49.7 and long-term through 6.48.6 are vulnerable to a privilege escalation issue. A…
CVE-2018-14847 — Critical (CVSS 9.1): MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary files and remote authenticated…
CVE-2022-45313 — High (CVSS 8.8): Mikrotik RouterOs before stable v7.5 was discovered to contain an out-of-bounds read in the hotspot process. This…

All CVEs affecting Mikrotik Routeros →

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CVE-2026-46803 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Portal product of Oracle Fusion Middleware (component: Security Framework).…
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Browse all CWE-306 (Missing Authentication for Critical Function) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

35.130.111.146 (ipv4-addr)
35.130.111.98 (ipv4-addr)
27.110.176.222 (ipv4-addr)