Unauthorized Remote Access Vulnerability in Calix Residential Router Firmware

CVE-2026-75501

What is CVE-2026-75501?

A security flaw in the Calix EXOS firmware for GS7 XGS (GS5239XG) residential routers allows remote, unauthenticated attackers to manipulate NAT port-forwarding rules through the UPnP WANIPConnection service. This vulnerability exposes the MiniUPnPd control endpoint on the WAN interface via TCP port 5000 without appropriate access controls. By sending specially crafted SOAP requests, attackers can add, delete, or enumerate port mappings and query the external IP address. If exploited, this could lead to the bypass of firewall/NAT protections, potentially exposing internal LAN services to the public internet, posing a significant risk to user privacy and security.

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