Three vulnerabilities were reported in the Libevent library that allow for out-of-bounds reads and denial of service (DoS) attacks. These were fixed in the Libevent library and these changes were ported to Mozilla code.
The search_make_new function in evdns.c in libevent before 2.1.6-beta allows attackers to cause a denial of service (out-of-bounds read) via an empty hostname.