# CVE-2026-16331: D-Link DNS-320 save_ajax.php unrestricted upload

> Remote attackers can upload malicious files via save_ajax.php on D-Link DNS-320 devices, potentially leading to code execution.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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:** 21 Jul 2026
- **Updated:** 22 Jul 2026
- **Also known as:** GHSA-hfvv-f4x9-469c

## What is CVE-2026-16331?

CVE-2026-16331 is a medium-severity vulnerability in D-Link DNS-320, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security vulnerability has been detected in D-Link DNS-320 1.0.2. This affects an unknown function of the file /web/function/save_ajax.php. Such manipulation of the argument Malicious Handler leads to unrestricted upload. The attack can be executed remotely. The exploit has been disclosed publicly and may be used.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-16331?


## How do I fix CVE-2026-16331?

No fix has been published for CVE-2026-16331 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-16331 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16331 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-16331 and fix it if it is affected.

What it is: CVE-2026-16331 is a medium-severity vulnerability in D-Link DNS-320, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-16331 exists.

Affected product: D-Link DNS-320. 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-2026-16331/ (Markdown: https://insights.sbomify.com/CVE-2026-16331/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16331
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16331
- OSV: https://osv.dev/vulnerability/CVE-2026-16331

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-16331/
Summaries are generated and may contain mistakes; the official description above is the record.