The remote host is missing an update to krb5 announced via advisory DSA 520-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20520-1

In their advisory MITKRB5-SA-2004-001, the MIT Kerberos announced the existence of buffer overflow vulnerabilities in the krb5_aname_to_localname function. This function is only used if aname_to_localname is enabled in the configuration (this is not enabled by default). For the current stable distribution (woody), this problem has been fixed in version 1.2.4-5woody5. For the unstable distribution (sid), this problem has been fixed in version 1.3.3-2. We recommend that you update your krb5 package.