# CVE-2019-3979: RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and below are vulnerable to a DNS unrelated data attack.


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-hxg2-8cqf-77j7

## What is CVE-2019-3979?

CVE-2019-3979 is a high-severity vulnerability in Mikrotik Routeros, published on 28 Oct 2019. 

### Official description

RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and below are vulnerable to a DNS unrelated data attack. The router adds all A records to its DNS cache even when the records are unrelated to the domain that was queried. Therefore, a remote attacker controlled DNS server can poison the router's DNS cache via malicious responses with additional and untrue records.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2019-3979?

It affects 1 product.


Products: Mikrotik Routeros.

## How do I fix CVE-2019-3979?

No fix has been published for CVE-2019-3979 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-3979 being exploited?

There is no known exploitation of CVE-2019-3979 in the wild and no public exploit code.

## Other vulnerabilities in Mikrotik Routeros

- [CVE-2018-7445](https://insights.sbomify.com/CVE-2018-7445/): MikroTik RouterOS Stack-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2026-86060](https://insights.sbomify.com/CVE-2026-86060/): MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command (critical 9.2, exploited in the wild)
- [CVE-2018-14847](https://insights.sbomify.com/CVE-2018-14847/): MikroTik Router OS Directory Traversal (critical 9.1, exploited in the wild)
- [CVE-2026-67277](https://insights.sbomify.com/CVE-2026-67277/): MikroTik RouterOS Missing Authentication for Critical Function (high 8.8, exploited in the wild)
- [CVE-2026-67279](https://insights.sbomify.com/CVE-2026-67279/): Mikrotik RouterOS Improper Enforcement of Behavioral Workflow (medium 6.9, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-3979 and fix it if it is affected.

What it is: CVE-2019-3979 is a high-severity vulnerability in Mikrotik Routeros, published on 28 Oct 2019. 
Exploitation: There is no known exploitation of CVE-2019-3979 in the wild and no public exploit code.

Affected product: Mikrotik Routeros. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2019-3979/ (Markdown: https://insights.sbomify.com/CVE-2019-3979/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-3979
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-3979
- OSV: https://osv.dev/vulnerability/CVE-2019-3979

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-3979/
Summaries are generated and may contain mistakes; the official description above is the record.