The remote host is missing an update to bnc announced via advisory DSA 595-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20595-1

Leon Juranic discovered that BNC, an IRC session bouncing proxy, does not always protect buffers from being overwritten. This could exploited by a malicious IRC server to overflow a buffer of limited size and execute arbitrary code on the client host. For the stable distribution (woody) this problem has been fixed in version 2.6.4-3.3. This package does not exist in the testing or unstable distributions. We recommend that you upgrade your bnc package.