# CVE-2026-6559: Wavlink WL-WN579A3 login.cgi sub_401F80 cross site scripting

> Remote attackers can execute arbitrary scripts via the Hostname parameter in the login interface of Wavlink WL-WN579A3 routers.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Apr 2026
- **Updated:** 20 Apr 2026
- **Also known as:** GHSA-x8cm-r99c-gv26

## What is CVE-2026-6559?

CVE-2026-6559 is a medium-severity cross-site scripting vulnerability in Wavlink WL-WN579A3, published on 19 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A weakness has been identified in Wavlink WL-WN579A3 220323. This affects the function sub_401F80 of the file /cgi-bin/login.cgi. This manipulation of the argument Hostname causes cross site scripting. Remote exploitation of the attack is possible. Upgrading the affected component is recommended. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-6559?


## How do I fix CVE-2026-6559?

No fix has been published for CVE-2026-6559 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6559 being exploited?

There is no known exploitation of CVE-2026-6559 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6559 and fix it if it is affected.

What it is: CVE-2026-6559 is a medium-severity cross-site scripting vulnerability in Wavlink WL-WN579A3, published on 19 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-6559 in the wild and no public exploit code.

Affected product: Wavlink WL-WN579A3. 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-2026-6559/ (Markdown: https://insights.sbomify.com/CVE-2026-6559/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6559
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6559
- OSV: https://osv.dev/vulnerability/CVE-2026-6559

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6559/
Summaries are generated and may contain mistakes; the official description above is the record.