Software engineer Carl Schou revealed on Twitter that the network name completely disables the device connecting, and cannot be reset when rebooting the device or resetting the iPhone’s network settings.

 To restore functionality, users would have to manually edit an iPhone backup and remove the malicious network name from within the files in iOS and macOS.

Schou has been rather good at finding wi-fi errors in iPhones lately.  Last month, he discovered that iOS devices are not able to join wi-fi networks with names such as “%p%s%s%s%s%n”, with the issue also stopping local network features like AirDrop.

It appears that the issue is with the percentage sign followed by a letter is used in programming languages to format variables (names that hold values) into an output string – a series of characters used to store information, similar to a sentence in English. Apple's supercool programming means that the wi-fi system on iPhones and iPads passes the network name (the ‘Service Set IDentifier’ or SSID) to an internal library that is performing string formatting, which causes an arbitrary memory write (taking information and moving it somewhere else) and buffer overflow.

Arbitrary memory is memory in the device’s local system, which is reformatted by the string, while a buffer is a process that lets a device operate a process without affecting other processes. If this is ‘overflowed’ it means that the command is also writing to other areas it should not be.

Of course the Tame Apple Press insists that it is nothing to worry about and all unease Apple fanboys might have over such bad programming can be simply resolved by buying another expensive Apple product.  Apple is not saying anything about the bug, and presumably believes it will go away.