The tcp_request function in Dnsmasq before 2.73rc4 does not properly handle the return value of the setup_reply function, which allows remote attackers to read process memory and cause a denial of service (out-of-bounds read and crash) via a malformed DNS request.
http://lists.opensuse.org/opensuse-updates/2015-05/msg00013.html
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2015q2/009382.html
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2015q2/009387.html
https://security.gentoo.org/glsa/201512-01
http://www.debian.org/security/2015/dsa-3251
http://www.oracle.com/technetwork/topics/security/bulletinjul2015-2511963.html