https://wccftech.com/ios-bug-causes-certain-network-name-to-permanently-disable-wifi-on-iphone/

Every now and then security researchers discover bugs that might be devastating for your iPhone. However, while most of them are visible on the front end, others make their way for a potential jailbreak. Needless to say, some iOS bugs disrupt the normal functionality of your iPhone if you are not careful. For instance, a new iOS bug has been discovered that causes a certain network name to disable the WiFi on your iPhone.

The end result is simple, you would not be able to connect to any other WiFi, completely disrupting the routine tasks. The iOS bug was discovered by Carl Schou, who found that joining a WiFi network with the name "%p%s%s%s%s%n" with your iPhone will permanently disable the WiFi functionality. Moreover, changing the hotspot's SSID did not help eliminate the effects either. Moreover, rebooting your iPhone will have no effect as well (via BleepingComputer).