# CVE-2018-3953: Command injection in ESeries E1200

> Attackers can execute arbitrary OS commands on Linksys E-Series routers by injecting malicious data into the Router Name field via the web interface.

- **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:** 17 Sep 2024
- **Also known as:** GHSA-frx4-39mr-82xv

## What is CVE-2018-3953?

CVE-2018-3953 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

Devices in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04) are susceptible to OS command injection vulnerabilities due to improper filtering of data passed to and retrieved from NVRAM. Data entered into the 'Router Name' input field through the web portal is submitted to apply.cgi as the value to the 'machine_name' POST parameter. When the 'preinit' binary receives the SIGHUP signal, it enters a code path that continues until it reaches offset 0x0042B5C4 in the 'start_lltd' function. Within the 'start_lltd' function, a 'nvram_get' call is used to obtain the value of the user-controlled 'machine_name' NVRAM entry. This value is then entered directly into a command intended to write the host name to a file and subsequently executed.

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

## Which versions are affected by CVE-2018-3953?

It affects 2 products.


Products: Linksys E1200 Firmware, Linksys E2500 Firmware.

## How do I fix CVE-2018-3953?

No fix has been published for CVE-2018-3953 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-3953 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-3953 exists.

Public exploit code:

- Linksys E1500/E2500 Remote Command Execution (metasploit)
- Linksys E1500/E2500 apply.cgi Remote Command Injection (metasploit)

## 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-2018-3953 and fix it if it is affected.

What it is: CVE-2018-3953 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-3953 exists.

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-2018-3953/ (Markdown: https://insights.sbomify.com/CVE-2018-3953/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-3953
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-3953
- OSV: https://osv.dev/vulnerability/CVE-2018-3953

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-3953/
Summaries are generated and may contain mistakes; the official description above is the record.