Zdenek Dohnal wrote:
CUPS discovery is designed to run on secure, private LAN, so it is expected that you have a protection against somebody connecting to your WIFI.
That was a reasonable assumption in the 1980s. It's 2021 now, and every program that communicates must cope with a hostile environment.
Here in the third millennium we have laptops moving between networks. There are public hotspots and mobile Internet, plenty of connections that aren't private LANs. Home routers are typically crap and never get any security updates, and the Insecurity of Things ensures that there are easily cracked devices in every home and office. As for wifi, it has a long history of flawed security protocols. A recent study found three protocol design flaws in the standards, including the latest WPA3 specification, and nine implementation defects that can be used to attack devices that trust the wifi network to protect them. Assuming that all the nodes on the local link are friendly is criminally naïve.
Björn Persson