Andrey V. Elsukov

https://github.com/zmap/zmap/blob/baee71e5d67ef95f3c040818c04635762158dfa6/src/probe_modules/module_dns.c#L763 buf_len isn't initialized for num_questions == 1 and this leads to invoking sendto() with zero buffer length and in result we have EINVAL. You can reproduce the problem with...