The remote host is missing an update to tcpdump announced via advisory DSA 261-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20261-1

A problem has been discovered in tcpdump, a powerful tool for network monitoring and data acquisition. An attacker is able to send a specially crafted RADIUS network packet which causes tcpdump to enter an infinite loop. For the stable distribution (woody) this problem has been fixed in version 3.6.2-2.4. The old stable distribution (potato) does not seem to be affected by this problem. The unstable distribution (sid) is not affected by this problem anymore. We recommend that you upgrade your tcpdump package.