The remote host is missing an update to yaws announced via advisory DSA 1740-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201740-1

It was discovered that yaws, a high performance HTTP 1.1 webserver, is prone to a denial of service attack via a request with a large HTTP header. For the stable distribution (lenny), this problem has been fixed in version 1.77-3+lenny1. For the oldstable distribution (etch), this problem has been fixed in version 1.65-4etch1. For the testing distribution (squeeze) and the unstable distribution (sid), this problem has been fixed in version 1.80-1. We recommend that you upgrade your yaws package.