# CVE-2016-7406: Code injection in n/a

> Remote attackers can execute arbitrary code on Dropbear SSH servers by injecting format string specifiers into username or host arguments.

- **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:** Yes
- **Published:** 3 Mar 2017
- **Updated:** 4 Nov 2025
- **Also known as:** DEBIAN-CVE-2016-7406, GHSA-jvpx-9hv9-4qf6, UBUNTU-CVE-2016-7406

## What is CVE-2016-7406?

CVE-2016-7406 is a critical code injection vulnerability in n/a, published on 3 Mar 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Format string vulnerability in Dropbear SSH before 2016.74 allows remote attackers to execute arbitrary code via format string specifiers in the (1) username or (2) host argument.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2016-7406?

It affects 1 product.


Products: Dropbear Ssh Project Dropbear Ssh.

## How do I fix CVE-2016-7406?

Upgrade to a fixed version.

## Is CVE-2016-7406 being exploited?

There is no known exploitation of CVE-2016-7406 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2016-7407](https://insights.sbomify.com/CVE-2016-7407/): Code injection in n/a (critical 9.8)
- [CVE-2016-7408](https://insights.sbomify.com/CVE-2016-7408/): Command injection in n/a (high 8.8)
- [CVE-2020-36254](https://insights.sbomify.com/CVE-2020-36254/): Path traversal in n/a (high 8.1)
- [CVE-2007-1099](https://insights.sbomify.com/CVE-2007-1099/): Security feature bypass in n/a (high 7.5)
- [CVE-2004-2486](https://insights.sbomify.com/CVE-2004-2486/): Use after free in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-7406 and fix it if it is affected.

What it is: CVE-2016-7406 is a critical code injection vulnerability in n/a, published on 3 Mar 2017. 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-2016-7406 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-2016-7406/ (Markdown: https://insights.sbomify.com/CVE-2016-7406/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-7406
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-7406
- OSV: https://osv.dev/vulnerability/CVE-2016-7406

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-7406/
Summaries are generated and may contain mistakes; the official description above is the record.