CVE-2020-25682

A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability
was discovered in the way dnsmasq extract names from DNS packets before
validating them with DNSSEC data. An attacker on the network, who can
create valid DNS replies, could use this flaw to cause an overflow with
arbitrary data in a heap-allocated memory, possibly executing code on the
machine. The flaw is in the rfc1035.c:extract_name() function, which writes
data to the memory pointed by name assuming MAXDNAME*2 bytes are available
in the buffer. However, in some code execution paths, it is possible
extract_name() gets passed an offset from the base buffer, thus reducing,
in practice, the number of available bytes that can be written in the
buffer. The highest threat from this vulnerability is to data
confidentiality and integrity as well as system availability.