numberInput = 99999999999999999999999999999999999.0;You should know that floats and doubles are the same on Arduino, and are accurate to only 6-7 digits. So, this number is unreasonable in terms of significant digits.
With a bit of thought you can plan ahead when using dtostrf() and allocate a sensible amount of space. A 10 character array should suffice in reasonable situations. One character for sign and one for decimal point leaves 7 for significant figures - any more would be nonsense. Don't forget the terminating zero byte!