This indicates an attack attempt to exploit an Information Disclosure vulnerability in Dnsmasq.
The vulnerability is due to an improper boundary check in the application when handling an overly large request. A remote attacker can exploit this to gain access to sensitive information, leading to possible ASLR bypass.
Dnsmasq versions prior to 2.78
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Upgrade to the latest version available from the website.