# CVE-2026-18607: Wavlink NU516 lighttpd upload.cgi strcpy stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the lighttpd upload.cgi component via the HTTP_COOKIE argument, potentially leading to code execution on Wavlink routers.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** GHSA-82rw-j2xw-2766

## What is CVE-2026-18607?

CVE-2026-18607 is a high-severity memory corruption vulnerability in Wavlink NU516, published on 3 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security vulnerability has been detected in Wavlink WN572, WN570H, WN573, WN529, WN530, WN531, WN535, etc. WN529, WN530, WN531, WN535, WN536, WN551, WN557 and NU516 up to 20260609. Affected by this issue is the function strcpy of the file upload.cgi of the component lighttpd. The manipulation of the argument HTTP_COOKIE leads to stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-18607?


## How do I fix CVE-2026-18607?

No fix has been published for CVE-2026-18607 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18607 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18607 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18607 and fix it if it is affected.

What it is: CVE-2026-18607 is a high-severity memory corruption vulnerability in Wavlink NU516, published on 3 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18607 exists.

Affected product: Wavlink NU516. 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-2026-18607/ (Markdown: https://insights.sbomify.com/CVE-2026-18607/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18607
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18607
- OSV: https://osv.dev/vulnerability/CVE-2026-18607

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18607/
Summaries are generated and may contain mistakes; the official description above is the record.