The remote host is missing an update to librpcsecgss announced via advisory DSA 1368-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201368-1

It was discovered that a buffer overflow of the library for secure RPC communication over the rpcsec_gss protocol allows the execution of arbitrary code. The oldstable distribution (sarge) doesn't contain librpcsecgss. For the stable distribution (etch) this problem has been fixed in version 0.14-2etch1. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you upgrade your librpcsecgss packages.