The remote host is missing an update to pdns-recursor announced via advisory DSA 1968-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201968-1

It was discovered that pdns-recursor, the PowerDNS recursive name server, contains several vulnerabilities: A buffer overflow can be exploited to crash the daemon, or potentially execute arbitrary code (CVE-2009-4009). A cache poisoning vulnerability may allow attackers to trick the server into serving incorrect DNS data (CVE-2009-4010). For the old stable distribution (etch), fixed packages will be provided soon. For the stable distribution (lenny), these problems have been fixed in version 3.1.7-1+lenny1. For the unstable distribution (sid), these problems have been fixed in version 3.1.7.2-1. We recommend that you upgrade your pdns-recursor package.