The remote host is missing an update to heimdal announced via advisory DSA 504-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20504-1

Evgeny Demidov discovered a potential buffer overflow in a Kerberos 4 component of heimdal, a free implementation of Kerberos 5. The problem is present in kadmind, a server for administrative access to the Kerberos database. This problem could perhaps be exploited to cause the daemon to read a negative amount of data which could lead to unexpected behaviour. For the stable distribution (woody) this problem has been fixed in version 0.4e-7.woody.9. For the unstable distribution (sid) this problem has been fixed in version 0.6.2-1. We recommend that you upgrade your heimdal and related packages.