The remote host is missing an update to hiki announced via advisory DSA 1119-1. Akira Tanaka discovered a vulnerability in Hiki Wiki, a Wiki engine written in Ruby that allows remote attackers to cause a denial of service via high CPU consumption using by performing a diff between large and specially crafted Wiki pages.
For the stable distribution (sarge) this problem has been fixed in version 0.6.5-2. For the unstable distribution (sid) this problem has been fixed in version 0.8.6-1. We recommend that you upgrade your hiki package. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201119-1