# CVE-2018-19986: Command injection in n/a

> Attackers can execute arbitrary commands on D-Link routers by injecting shell metacharacters into the RemotePort parameter of the SetRouterSettings message.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 May 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-3phf-fpc4-v2qv

## What is CVE-2018-19986?

CVE-2018-19986 is a critical command injection vulnerability in n/a, published on 13 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the /HNAP1/SetRouterSettings message, the RemotePort parameter is vulnerable, and the vulnerability affects D-Link DIR-818LW Rev.A 2.05.B03 and DIR-822 B1 202KRb06 devices. In the SetRouterSettings.php source code, the RemotePort parameter is saved in the $path_inf_wan1."/web" internal configuration memory without any regex checking. And in the IPTWAN_build_command function of the iptwan.php source code, the data in $path_inf_wan1."/web" is used with the iptables command without any regex checking. A vulnerable /HNAP1/SetRouterSettings XML message could have shell metacharacters in the RemotePort element such as the `telnetd` string.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2018-19986?

It affects 2 products.


Products: D-Link Dir-818lw Firmware, D-Link Dir-822 Firmware.

## How do I fix CVE-2018-19986?

No fix has been published for CVE-2018-19986 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-19986 being exploited?

There is no known exploitation of CVE-2018-19986 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-19987](https://insights.sbomify.com/CVE-2018-19987/): Command injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-19986 and fix it if it is affected.

What it is: CVE-2018-19986 is a critical command injection vulnerability in n/a, published on 13 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-19986 in the wild and no public exploit code.

Affected product: n/a. 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-2018-19986/ (Markdown: https://insights.sbomify.com/CVE-2018-19986/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-19986
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-19986
- OSV: https://osv.dev/vulnerability/CVE-2018-19986

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-19986/
Summaries are generated and may contain mistakes; the official description above is the record.