Summary
The remote host is missing an update to the system as announced in the referenced advisory.
Solution
Update your system with the appropriate patches or software upgrades.
http://doc.powerdns.com/security-policy.html
http://www.vuxml.org/freebsd/b21790a5-02fb-11dd-bd06-0017319806e7.html
Insight
The following package is affected: powerdns-recursor