One common (forgotten) security issue that exists in our home - Vulnerabilities that will NEVER be patched because the system in unsupported (EOL) (Router, TV, IoT, or anything that can connect to internet).

For Example - The security researchers disclosed their findings to D-Link on September 22. Within 24 hours the hardware vendor had confirmed the vulnerability, and three days later, D-Link said that as the products are at End of Life (EOL) support, no patch will be released.

https://www.zdnet.com/article/d-link-routers-contain-remote-code-execution-vulnerability/