VU#756733: Calix GS7 XGS GS5239XG residential router contains missing authentication vulnerability

Summary

Overview The Calix GS7 XGS GS5239XG router running firmware EXOS/6.6.47 contains a missing authentication vulnerability that exposes its UPnP (Universal Plug and Play) WANIPConnection service on the public WAN interface. Description Calix GS7 XGS GS5239XG is a residential gateway that provides routing, NAT, and firewall functionality for home networks. The device includes the Universal Plug and Play (UPnP) service implemented via MiniUPnPd 2.3.7, a lightweight software program that provides features such as automatic port forwarding for applications and devices on the LAN. By default, the UPnP service is exposed on the device’s WAN interface and does not require authentication. CVE-2026-75501 In affected firmware versions, the router binds its UPnP WANIPConnection SOAP service to the public WAN interface on TCP port 5000. Because the... Related CVEs: CVE-2026-75501.

Why it matters

CERT/CC notes often cover coordinated disclosures, multi-vendor exposure, infrastructure risk, or cases where remediation guidance is still developing.

Operator check

Review the CERT/CC Vulnerability Note and compare the affected vendor and product list against your inventory. Apply vendor fixes or compensating controls for GS7 XGS GS5239XG residential router where available.

Sources