The remote host is missing an update to zonecheck announced via advisory DSA 2056-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202056-1

It was discovered that in zonecheck, a tool to check DNS configurations, the CGI does not perform sufficient sanitation of user input an attacker can take advantage of this and pass script code in order to perform cross-site scripting attacks. For the stable distribution (lenny), this problem has been fixed in version 2.0.4-13lenny1. For the testing distribution (squeeze), this problem has been fixed in version 2.1.1-1. For the testing distribution (sid), this problem has been fixed in version 2.1.1-1. We recommend that you upgrade your zonecheck packages.