An unpatched vulnerability in Calix GS7 XGS (GS5239XG) residential routers used by multiple U.S. broadband providers allows remote, unauthenticated attackers to create port-forwarding rules that can expose local network devices to the public internet. [...]

https://www.bleepingcomputer.com/news/security/unpatched-calix-flaw-lets-hackers-bypass-nat-to-expose-internal-devices/