# CVE-2026-3704: Wavlink NU516U1 Incomplete Fix CVE-2025-10959 firewall.cgi sub_405B2C command injection

> Remote attackers can execute arbitrary commands on Wavlink NU516U1 routers via a command injection flaw in the firewall CGI script.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Mar 2026
- **Updated:** 10 Mar 2026
- **Also known as:** GHSA-v25j-jp29-j537

## What is CVE-2026-3704?

CVE-2026-3704 is a medium-severity command injection vulnerability in Wavlink NU516U1, published on 8 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability has been found in Wavlink NU516U1 251208. This vulnerability affects the function sub_405B2C of the file /cgi-bin/firewall.cgi of the component Incomplete Fix CVE-2025-10959. The manipulation leads to command injection. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. It is recommended to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-3704?

It affects 1 product.


Products: Wavlink Wl-Nu516u1 Firmware.

## How do I fix CVE-2026-3704?

No fix has been published for CVE-2026-3704 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3704 being exploited?

There is no known exploitation of CVE-2026-3704 in the wild and no public exploit code.

## Other vulnerabilities in Wavlink NU516U1

- [CVE-2026-3703](https://insights.sbomify.com/CVE-2026-3703/): Wavlink NU516U1 login.cgi sub_401A10 out-of-bounds write (critical 9.3)
- [CVE-2026-4861](https://insights.sbomify.com/CVE-2026-4861/): Wavlink WL-NU516U1 nas.cgi ftext stack-based overflow (high 8.7)
- [CVE-2026-3612](https://insights.sbomify.com/CVE-2026-3612/): Wavlink WL-NU516U1 OTA Online Upgrade adm.cgi sub_405AF4 command injection (high 8.6)
- [CVE-2026-3613](https://insights.sbomify.com/CVE-2026-3613/): Wavlink WL-NU516U1 login.cgi sub_401A0C stack-based overflow (high 8.6)
- [CVE-2026-2615](https://insights.sbomify.com/CVE-2026-2615/): Wavlink WL-NU516U1 firewall.cgi singlePortForwardDelete command injection (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3704 and fix it if it is affected.

What it is: CVE-2026-3704 is a medium-severity command injection vulnerability in Wavlink NU516U1, published on 8 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-3704 in the wild and no public exploit code.

Affected product: Wavlink NU516U1. 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-2026-3704/ (Markdown: https://insights.sbomify.com/CVE-2026-3704/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3704
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3704
- OSV: https://osv.dev/vulnerability/CVE-2026-3704

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3704/
Summaries are generated and may contain mistakes; the official description above is the record.