The remote host is missing an update to ircii-pana announced via advisory DSA 307-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20307-1

Timo Sirainen discovered several problems in BitchX, a popular client for Internet Relay Chat (IRC). A malicious server could craft special reply strings, triggering the client to write beyond buffer boundaries or allocate a negative amount of memory. This could lead to a denial of service if the client only crashes, but may also lead to executing of arbitrary code under the user id of the chatting user. For the stable distribution (woody) these problems have been fixed in version 1.0-0c19-1.1. For the old stable distribution (potato) these problems have been fixed in version 1.0-0c16-2.1. For the unstable distribution (sid) these problems have been fixed in version 1.0-0c19-8. We recommend that you upgrade your BitchX package.