CVE-2020-25683

A flaw was found in dnsmasq before version 2.83. A heap-based buffer
overflow was discovered in dnsmasq when DNSSEC is enabled and before it
validates the received DNS entries. A remote attacker, who can create valid
DNS replies, could use this flaw to cause an overflow in a heap-allocated
memory. This flaw is caused by the lack of length checks in
rfc1035.c:extract_name(), which could be abused to make the code execute
memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq,
resulting in a denial of service. The highest threat from this
vulnerability is to system availability.