CVE-2026-77218 PLANET Technology Corp. CVE debrief

Who should care

Network administrators and security teams responsible for managing PLANET GS-4210-16P2S V3 devices should assess exposure and apply firmware updates. They should also review compensating controls for exposed systems, monitor for suspicious activity, and verify device inventory and patch status.

Why it matters

Authenticated stack buffer overflow vulnerabilities in PLANET GS-4210-16P2S V3 firmware before 3.441b260626 pose a medium risk of denial of service. Network administrators and security teams should assess exposure, apply firmware updates, and monitor for suspicious activity.

• Denial of service via crashing CGI process or web management service
• Potential disruption to network operations
• Need for firmware updates to remediate vulnerabilities
• Verification of device inventory and patch status required

Technical summary

The PLANET GS-4210-16P2S V3 firmware before 3.441b260626 contains authenticated stack buffer overflow vulnerabilities in /cgi-bin/dispatcher.cgi. A remote authenticated attacker can send a crafted request to crash the CGI process or web management service, resulting in denial of service. The vulnerabilities involve the web_login_first_post, web_sys_enablePasswd_post, and web_sys_localUser_post handlers, which copy POST parameters into fixed-size stack buffers without length validation. This can lead to potential denial of service via crashing CGI process or web management service.

Defensive priority

Medium

Recommended defensive actions

• Review and apply firmware updates for PLANET GS-4210-16P2S V3
• Restrict access to the web management service
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the authenticated stack buffer overflow vulnerabilities in PLANET GS-4210-16P2S V3 firmware before 3.441b260626. Evidence is limited to public sources and may not be comprehensive. Defenders should verify affected scope and apply firmware updates according to vendor guidance. 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

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.