The c-ares function `ares_parse_naptr_reply()`, which is used for parsing NAPTR responses, could be triggered to read memory outside of the given input buffer if the passed in DNS response packet was crafted in a particular way.

Affected: Ubuntu:14.04:LTS: c-ares, Ubuntu:16.04:LTS: c-ares

It was discovered that c-ares incorrectly handled certain NAPTR responses. A remote attacker could possibly use this issue to cause applications using c-ares to crash, resulting in a denial of service.