# CVE-2026-5354: Trendnet TEW-657BRM setup.cgi vpn_connect os command injection

> Remote attackers can execute arbitrary OS commands via the vpn_connect function in the discontinued Trendnet TEW-657BRM router.

- **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:** 2 Apr 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-j222-qjwr-c34g

## What is CVE-2026-5354?

CVE-2026-5354 is a medium-severity command injection vulnerability in Trendnet TEW-657BRM, published on 2 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw has been found in Trendnet TEW-657BRM 1.00.1. Affected by this vulnerability is the function vpn_connect of the file /setup.cgi. Executing a manipulation of the argument policy_name can lead to os command injection. The attack can be executed remotely. The exploit has been published and may be used. The vendor confirms, that "[t]he product in question (...) has been discontinued and end of life since June 23, 2011, that is more than 14 years ago. We no longer provide support for this product, so we are not able to confirm the vulnerabilities. We will make an announcement on our website's product support page and notify customers who registered their products with us." This vulnerability only affects products that are no longer supported by the maintainer.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-77 (Improper Neutralization of Special Elements used in a Command)

## Which versions are affected by CVE-2026-5354?

It affects 1 product.


Products: Trendnet Tew-657brm Firmware.

## How do I fix CVE-2026-5354?

No fix has been published for CVE-2026-5354 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5354 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-5354 exists.

## Other vulnerabilities in Trendnet TEW-657BRM

- [CVE-2026-5349](https://insights.sbomify.com/CVE-2026-5349/): Trendnet TEW-657BRM setup.cgi add_apcdb stack-based overflow (high 8.7)
- [CVE-2026-5350](https://insights.sbomify.com/CVE-2026-5350/): Trendnet TEW-657BRM setup.cgi update_pcdb stack-based overflow (high 8.7)
- [CVE-2025-65202](https://insights.sbomify.com/CVE-2025-65202/): Command injection in n/a (high 8.0)
- [CVE-2026-5351](https://insights.sbomify.com/CVE-2026-5351/): Trendnet TEW-657BRM setup.cgi add_wps_client os command injection (medium 5.3)
- [CVE-2026-5352](https://insights.sbomify.com/CVE-2026-5352/): Trendnet TEW-657BRM setup.cgi edit os command injection (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5354 and fix it if it is affected.

What it is: CVE-2026-5354 is a medium-severity command injection vulnerability in Trendnet TEW-657BRM, published on 2 Apr 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-2026-5354 exists.

Affected product: Trendnet TEW-657BRM. 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-2026-5354/ (Markdown: https://insights.sbomify.com/CVE-2026-5354/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5354
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5354
- OSV: https://osv.dev/vulnerability/CVE-2026-5354

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5354/
Summaries are generated and may contain mistakes; the official description above is the record.