What’s Vulnerable › Vulnerabilities

CVE-2026-77218: PLANET GS-4210-16P2S V3 Stack Buffer Overflow via dispatcher.cgi Credential Handlers

• Severity: medium (CVSS 4.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-28 · updated 2026-09-08
• Weakness: CWE-121

Description

PLANET GS-4210-16P2S V3 firmware before 3.441b260626 contains authenticated stack buffer overflow vulnerabilities in /cgi-bin/dispatcher.cgi. The web_login_first_post handler copies the usrPass POST parameter into a fixed-size stack buffer without length validation, the web_sys_enablePasswd_post handler copies the enbPass POST parameter into a fixed-size stack buffer without length validation, and the web_sys_localUser_post handler copies the usrName and usrPass POST parameters into fixed-size stack buffers without length validation. A remote authenticated attacker can send a crafted request to crash the CGI process or web management service, resulting in denial of service.

Affected products

• PLANET Technology Corp. PLANET GS-4210-16P2S V3: before 3.441b260626 — fixed in 3.441b260626

How to fix

Upgrade to a fixed version: PLANET Technology Corp. PLANET GS-4210-16P2S V3 3.441b260626. Check the vendor advisory for mitigations.

References

• https://www.planet.com.tw/en/support/security-advisory/10
• https://www.vulncheck.com/advisories/planet-gs-4210-16p2s-stack-buffer-overflow-via-dispatcher-cgi-credential-handlers

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