CVE-2026-75126 PLANET GS-4210-16P2S V3 Stack Buffer Overflow via dispatcher.cgi Standard Handlers
Authenticated attackers can trigger stack buffer overflows in multiple CGI handlers, causing denial of service on PLANET managed switches.
- 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-2026-75126?
CVE-2026-75126 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 multiple authenticated stack buffer overflow vulnerabilities in /cgi-bin/dispatcher.cgi. The following handlers copy attacker-controlled POST parameters into fixed-size stack buffers without length validation: web_vlan_membership_edit_dialog_post; web_dai_vlan_post; web_poe_alive_rmtip_post; web_sys_sntp_post; web_tool_upgradeManager_post; web_port_countersClr_post; web_rmon_statisticsClr_post; web_cablediag_copper_post; web_aaa_*Authlist* handlers; web_acl_mgmt_Rules_Apply_post; web_acl_mgmt_Rules_Edit_post; web_acl_*AceDel_post handlers; web_acl_*AceAdd/Edit_post handlers; web_acl_bindAdd_post; web_acl_bindEdit_post; web_snmp_v3view_add_post; web_snmp_v3group_add_post; web_snmp_v3community_add_post; web_snmp_v3host_add_post; web_snmp_notifyv3_add_post; web_snmp_v3user_add_post; web_snmpv3_remote_engineId_add_post; web_stp_globalSetting_post; web_isg_db_post; web_tacplus*_post handlers; web_dhcp_option82_post; and web_dhcp_port_option82_cid_post. A remote authenticated attacker can send crafted requests to crash the CGI process or web management service, resulting in denial of service.
Weakness: CWE-121
Which versions are affected by CVE-2026-75126?
How do I fix CVE-2026-75126?
No fix has been published for CVE-2026-75126 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-2026-75126 being exploited?
There is no known exploitation of CVE-2026-75126 in the wild and no public exploit code.
Sources
Also known as GHSA-r4jg-62xg-rrfv.