# CVE-2026-75123: PLANET GS-4210-16P2S V3 Command Injection via dispatcher.cgi web_smtp_test_post

> Authenticated attackers can execute arbitrary OS commands on PLANET GS-4210-16P2S V3 switches via unsanitized SMTP server input in the web interface.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-x4x6-gfv8-643f

## What is CVE-2026-75123?

CVE-2026-75123 is a high-severity command injection vulnerability in PLANET GS-4210-16P2S V3, published on 28 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

PLANET GS-4210-16P2S V3 firmware before 3.441b260626 contains an authenticated OS command injection vulnerability in /cgi-bin/dispatcher.cgi. The web_smtp_test_post handler incorporates a caller-supplied SMTP server value directly into a shell command without sanitization. A remote attacker with administrator web credentials can send a crafted SMTP server value to execute arbitrary operating-system commands on the device.

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

## Which versions are affected by CVE-2026-75123?


## How do I fix CVE-2026-75123?

No fix has been published for CVE-2026-75123 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75123 being exploited?

There is no known exploitation of CVE-2026-75123 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75123 and fix it if it is affected.

What it is: CVE-2026-75123 is a high-severity command injection vulnerability in PLANET GS-4210-16P2S V3, published on 28 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-75123 in the wild and no public exploit code.

Affected product: PLANET GS-4210-16P2S V3. 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-2026-75123/ (Markdown: https://insights.sbomify.com/CVE-2026-75123/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75123
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75123
- OSV: https://osv.dev/vulnerability/CVE-2026-75123

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-75123/
Summaries are generated and may contain mistakes; the official description above is the record.