# CVE-2026-4213: D-Link DNS-1550-04 gui_mgr.cgi cgi_myfavorite_verify stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in D-Link NAS devices via the gui_mgr.cgi script, potentially leading to arbitrary code execution.

- **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:** 16 Mar 2026
- **Updated:** 16 Mar 2026
- **Also known as:** GHSA-wqj8-xmhx-vvcm

## What is CVE-2026-4213?

CVE-2026-4213 is a high-severity memory corruption vulnerability in Dlink Dns-320 Firmware, published on 16 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was detected in D-Link DNS-120, DNR-202L, DNS-315L, DNS-320, DNS-320L, DNS-320LW, DNS-321, DNR-322L, DNS-323, DNS-325, DNS-326, DNS-327L, DNR-326, DNS-340L, DNS-343, DNS-345, DNS-726-4, DNS-1100-4, DNS-1200-05 and DNS-1550-04 up to 20260205. This vulnerability affects the function cgi_myfavorite_del_user/cgi_myfavorite_verify of the file /cgi-bin/gui_mgr.cgi. Performing a manipulation results in stack-based buffer overflow. The attack may be initiated remotely. The exploit is now public and may be used.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-4213?

It affects 20 products.


Products: Dlink Dnr-202l Firmware, Dlink Dnr-326 Firmware, Dlink Dns-1100-4 Firmware, Dlink Dns-1200-05 Firmware, Dlink Dns-120 Firmware, Dlink Dns-1550-04 Firmware, Dlink Dns-315l Firmware, Dlink Dns-320 Firmware, Dlink Dns-320l Firmware, Dlink Dns-320lw Firmware, Dlink Dns-321 Firmware, Dlink Dns-322l Firmware, Dlink Dns-323 Firmware, Dlink Dns-325 Firmware, Dlink Dns-326 Firmware, Dlink Dns-327l Firmware, Dlink Dns-340l Firmware, Dlink Dns-343 Firmware, Dlink Dns-345 Firmware, Dlink Dns-726-4 Firmware.

## How do I fix CVE-2026-4213?

No fix has been published for CVE-2026-4213 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4213 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-4213 exists.

## Other vulnerabilities in Dlink Dns-320 Firmware

- [CVE-2024-3272](https://insights.sbomify.com/CVE-2024-3272/): D-Link Multiple NAS Devices Use of Hard-Coded Credentials (critical 9.8, exploited in the wild)
- [CVE-2024-3273](https://insights.sbomify.com/CVE-2024-3273/): D-Link Multiple NAS Devices Command Injection (high 7.3, exploited in the wild)
- [CVE-2026-5211](https://insights.sbomify.com/CVE-2026-5211/): D-Link DNS-1550-04 app_mgr.cgi UPnP_AV_Server_Path_Del stack-based overflow (high 8.7)
- [CVE-2026-5212](https://insights.sbomify.com/CVE-2026-5212/): D-Link DNS-1550-04 webdav_mgr.cgi Webdav_Upload_File stack-based overflow (high 8.7)
- [CVE-2026-5213](https://insights.sbomify.com/CVE-2026-5213/): D-Link DNS-1550-04 account_mgr.cgi cgi_adduser_to_session stack-based overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4213 and fix it if it is affected.

What it is: CVE-2026-4213 is a high-severity memory corruption vulnerability in Dlink Dns-320 Firmware, published on 16 Mar 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-2026-4213 exists.

Affected product: Dlink Dns-320 Firmware. 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-2026-4213/ (Markdown: https://insights.sbomify.com/CVE-2026-4213/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4213
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4213
- OSV: https://osv.dev/vulnerability/CVE-2026-4213

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4213/
Summaries are generated and may contain mistakes; the official description above is the record.