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

High 8.6 Published Updated

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

Exploited in the wild
Not known
Login needed
An administrator
Attackable
Over the internet
Victim action needed
Not needed
Fix
None listed

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

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.

Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.

Is CVE-2026-75123 being exploited?

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

Sources

Also known as GHSA-x4x6-gfv8-643f.

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