The remote host is missing an update to radiusd-cistron announced via advisory DSA 321-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20321-1

radiusd-cistron contains a bug allowing a buffer overflow when a long NAS-Port attribute is received. This could allow a remote attacker to execute arbitrary code on the with the privileges of the RADIUS daemon (usually root). For the stable distribution (woody) this problem has been fixed in version 1.6.6-1woody1. For the old stable distribution (potato), this problem will be fixed in a later advisory. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you update your radiusd-cistron package.