CVE-2026-77218 PLANET GS-4210-16P2S V3 Stack Buffer Overflow via dispatcher.cgi Credential Handlers
Authenticated attackers can trigger stack buffer overflows in the web management interface of PLANET switches, causing a denial of service.
- 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-2026-77218?
CVE-2026-77218 is a medium-severity memory corruption 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 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.
Weakness: CWE-121
Which versions are affected by CVE-2026-77218?
How do I fix CVE-2026-77218?
No fix has been published for CVE-2026-77218 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-77218 being exploited?
There is no known exploitation of CVE-2026-77218 in the wild and no public exploit code.
Sources
Also known as GHSA-qx7g-cv57-953h.