The remote host is missing an update to libnids announced via advisory DSA 410-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20410-1

A vulnerability was discovered in libnids, a library used to analyze IP network traffic, whereby a carefully crafted TCP datagram could cause memory corruption and potentially execute arbitrary code with the privileges of the user executing a program which uses libnids (such as dsniff). For the current stable distribution (woody) this problem has been fixed in version 1.16-3woody1. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you update your libnids package.