# CVE-2018-3955: Command injection in ESeries E1200

> Authenticated attackers can execute arbitrary system commands via the Domain Name field in Linksys E-Series routers, gaining full device control.

- **Severity:** High 7.2 (`CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Oct 2018
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-v2p8-7jjc-gfv9

## What is CVE-2018-3955?

CVE-2018-3955 is a high-severity command injection vulnerability in Linksys ESeries E1200, published on 17 Oct 2018. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

An exploitable operating system command injection exists in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04). Specially crafted entries to network configuration information can cause execution of arbitrary system commands, resulting in full control of the device. An attacker can send an authenticated HTTP request to trigger this vulnerability. Data entered into the 'Domain Name' input field through the web portal is submitted to apply.cgi as the value to the 'wan_domain' POST parameter. The wan_domain data goes through the nvram_set process described above. When the 'preinit' binary receives the SIGHUP signal it enters a code path that calls a function named 'set_host_domain_name' from its libshared.so shared object.

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

## Which versions are affected by CVE-2018-3955?

It affects 2 products.


Products: Linksys E1200 Firmware, Linksys E2500 Firmware.

## How do I fix CVE-2018-3955?

No fix has been published for CVE-2018-3955 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-3955 being exploited?

There is no known exploitation of CVE-2018-3955 in the wild and no public exploit code.

## Other vulnerabilities in Linksys ESeries E1200

- [CVE-2022-38555](https://insights.sbomify.com/CVE-2022-38555/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-60690](https://insights.sbomify.com/CVE-2025-60690/): Memory corruption in n/a (high 8.8)
- [CVE-2025-60691](https://insights.sbomify.com/CVE-2025-60691/): Memory corruption in n/a (high 8.8)
- [CVE-2025-60692](https://insights.sbomify.com/CVE-2025-60692/): Memory corruption in n/a (high 8.4)
- [CVE-2025-60694](https://insights.sbomify.com/CVE-2025-60694/): Memory corruption in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-3955 and fix it if it is affected.

What it is: CVE-2018-3955 is a high-severity command injection vulnerability in Linksys ESeries E1200, published on 17 Oct 2018. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-3955 in the wild and no public exploit code.

Affected product: Linksys ESeries E1200. 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-2018-3955/ (Markdown: https://insights.sbomify.com/CVE-2018-3955/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-3955
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-3955
- OSV: https://osv.dev/vulnerability/CVE-2018-3955

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-3955/
Summaries are generated and may contain mistakes; the official description above is the record.