4859. [bug] A loop was possible when attempting to validate
unsigned CNAME responses from secure zones;
this caused a delay in returning SERVFAIL and
also increased the chances of encountering
CVE-2017-3145. [RT #46839]
4858. [security] Addresses could be referenced after being freed
in resolver.c, causing an assertion failure.
(CVE-2017-3145) [RT #46839]