Stack Buffer Overflow in PLANET GS-4210-16P2S Firmware
CVE-2026-77218

6.9MEDIUM

Key Information:

Vendor

Planet Technology Corp.

Status
Planet Gs-4210-16p2s V3
Vendor
CVE Published:
28 August 2026

What is CVE-2026-77218?

The firmware of PLANET GS-4210-16P2S contains multiple stack buffer overflow vulnerabilities due to insufficient length validation in various POST handlers within the /cgi-bin/dispatcher.cgi. Specifically, the handlers 'web_login_first_post', 'web_sys_enablePasswd_post', and 'web_sys_localUser_post' improperly copy user input into fixed-size buffers without adequate checks. This flaw allows an authenticated remote attacker to craft specific requests to trigger a crash of the CGI process or the web management service, leading to potential denial of service.

Affected Version(s)

PLANET GS-4210-16P2S V3 0 < 3.441b260626

References

https://www.planet.com.tw/en/support/security-advisory/10
vendor-advisorypatch
https://www.vulncheck.com/advisories/planet-gs-4210-16p2s...
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jincheng Wang (@winmt)
Professor Le Yu of Nanjing University of Posts and Telecommunications
Professor Xiapu Luo of The Hong Kong Polytechnic University
.