# CVE-2026-5020: Totolink A3600R Parameter cstecgi.cgi setNoticeCfg command injection

> Remote attackers can execute arbitrary commands on Totolink A3600R routers via the NoticeUrl parameter in cstecgi.cgi.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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:** 29 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-98vg-cqgx-463p

## What is CVE-2026-5020?

CVE-2026-5020 is a medium-severity command injection vulnerability in Totolink A3600R, published on 29 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 Totolink A3600R 4.1.2cu.5182_B20201102. Affected by this issue is the function setNoticeCfg of the file /cgi-bin/cstecgi.cgi of the component Parameter Handler. The manipulation of the argument NoticeUrl results in command injection. The attack may be launched remotely. The exploit is now public and may be used.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-5020?

It affects 1 product.


Products: Totolink A3600r Firmware.

## How do I fix CVE-2026-5020?

No fix has been published for CVE-2026-5020 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5020 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5020 exists.

## Other vulnerabilities in Totolink A3600R

- [CVE-2026-31027](https://insights.sbomify.com/CVE-2026-31027/): Memory corruption in n/a (critical 9.8)
- [CVE-2022-34993](https://insights.sbomify.com/CVE-2022-34993/): Hardcoded credentials in n/a (critical 9.8)
- [CVE-2022-25078](https://insights.sbomify.com/CVE-2022-25078/): Command injection in n/a (critical 9.8)
- [CVE-2026-1686](https://insights.sbomify.com/CVE-2026-1686/): Totolink A3600R app.so setAppEasyWizardConfig buffer overflow (high 8.7)
- [CVE-2024-7174](https://insights.sbomify.com/CVE-2024-7174/): TOTOLINK A3600R cstecgi.cgi setdeviceName buffer overflow (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5020 and fix it if it is affected.

What it is: CVE-2026-5020 is a medium-severity command injection vulnerability in Totolink A3600R, published on 29 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-2026-5020 exists.

Affected product: Totolink A3600R. 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-2026-5020/ (Markdown: https://insights.sbomify.com/CVE-2026-5020/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5020
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5020
- OSV: https://osv.dev/vulnerability/CVE-2026-5020

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5020/
Summaries are generated and may contain mistakes; the official description above is the record.