# CVE-2019-3924: Server-side request forgery in MikroTik RouterOS

> Remote attackers can exploit an intermediary vulnerability to bypass firewalls and scan networks by forcing the router to execute arbitrary network requests.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Feb 2019
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-4qcw-5w3m-2hfg

## What is CVE-2019-3924?

CVE-2019-3924 is a high-severity server-side request forgery vulnerability in Mikrotik Routeros, published on 20 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

MikroTik RouterOS before 6.43.12 (stable) and 6.42.12 (long-term) is vulnerable to an intermediary vulnerability. The software will execute user defined network requests to both WAN and LAN clients. A remote unauthenticated attacker can use this vulnerability to bypass the router's firewall or for general network scanning activities.

Weakness: CWE-441 (Unintended Proxy or Intermediary)

## Which versions are affected by CVE-2019-3924?

It affects 1 product.


Products: Mikrotik Routeros.

## How do I fix CVE-2019-3924?

No fix has been published for CVE-2019-3924 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-3924 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-3924 exists.

Public exploit code:

- MikroTik RouterOS < 6.43.12 (stable) / < 6.42.12 (long-term) - Firewall and NAT Bypass (exploitdb)

## 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-2019-3924 and fix it if it is affected.

What it is: CVE-2019-3924 is a high-severity server-side request forgery vulnerability in Mikrotik Routeros, published on 20 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-3924 exists.

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-2019-3924/ (Markdown: https://insights.sbomify.com/CVE-2019-3924/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-3924
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-3924
- OSV: https://osv.dev/vulnerability/CVE-2019-3924

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-3924/
Summaries are generated and may contain mistakes; the official description above is the record.