# CVE-2026-18589: Wavlink WL-NU516U1 nas.cgi change_password stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the password change function to execute arbitrary code on Wavlink WL-NU516U1 devices.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** GHSA-jfmw-hm93-c7jh

## What is CVE-2026-18589?

CVE-2026-18589 is a critical memory corruption vulnerability in Wavlink WL-NU516U1, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in Wavlink WL-NU516U1 708c073-mt7628. This impacts the function change_password of the file nas.cgi. The manipulation of the argument User1Passwd results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been made public and could be used. The affected component should be upgraded. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

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-2026-18589?


## How do I fix CVE-2026-18589?

No fix has been published for CVE-2026-18589 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18589 being exploited?

There is no known exploitation of CVE-2026-18589 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18589 and fix it if it is affected.

What it is: CVE-2026-18589 is a critical memory corruption vulnerability in Wavlink WL-NU516U1, published on 3 Aug 2026. 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-2026-18589 in the wild and no public exploit code.

Affected product: Wavlink WL-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-2026-18589/ (Markdown: https://insights.sbomify.com/CVE-2026-18589/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18589
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18589
- OSV: https://osv.dev/vulnerability/CVE-2026-18589

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18589/
Summaries are generated and may contain mistakes; the official description above is the record.