This works fine with spaces and other strange characters, no need to come up with more complicated ways.
If you must use find, the correct way is really tricky and uses obscure bash features like settings IFS to the empty string to split on null bytes and process substitution so that the loop doesn't run in a subshell (which would prevent it from modifying variables in the current environment):
while IFS= read -r -d '' file; do ... done < <(find /tmp -type f -print0)
