The remote host is missing an update to ez-ipupdate announced via advisory DSA 592-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20592-1

Ulf Härnhammar from the Debian Security Audit Project discovered a format string vulnerability in ez-ipupdate, a client for many dynamic DNS services. This problem can only be exploited if ez-ipupdate is running in daemon mode (most likely) with many but not all service types. For the stable distribution (woody) this problem has been fixed in version 3.0.11b5-1woody2. For the unstable distribution (sid) this problem has been fixed in version 3.0.11b8-8. We recommend that you upgrade your ez-ipupdate package.