Do NOT join this network if you see it. Once you do it will brick your iPhone and will need a Reset Network Settings to fix. iOS Settings > General > Reset > Reset Network Settings.
(NOTE: if you need to click ‘Reset Network Settings” you won’t lose any data or files on your phone except you will lose any saved Wi-Fi networks and passwords.)
There is a bug in the text parser in iOS that tries to interpret the % as an escape character. %20 is often used in URLs and JavaScript to identify space between words. You can see a full list of URL encodes here: https://www.w3schools.com/tags/ref_urlencode.ASP
You can play with this 074%097%115%111%110%032%076%097%109%098%032%105%115%032%065%087%069%083%079%077%069%033 and decode it here: http://www.unit-conversion.info/texttools/ascii/
Start this video at 22:58 to hear Steve talk about this vulnerability.
You can check out Steve Gibson’s show notes from this episode here: https://www.grc.com/sn/sn-824-notes.pdf or the written transcript of that episode here: https://www.grc.com/sn/sn-824.htm
Also read: https://howtoremove.guide/p-s-s-s-s-n-wireless-network/