Algorithmic complexity vulnerability in Hiki Wiki 0.6.0 through 0.6.5 and 0.8.0 through 0.8.5 allows remote attackers to cause a denial of service (CPU consumption) by performing a diff between large, crafted pages that trigger the worst case.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27507
http://www.vupen.com/english/advisories/2006/2643
http://www.securityfocus.com/bid/18785
http://www.debian.org/security/2006/dsa-1119
http://secunia.com/advisories/21150
http://secunia.com/advisories/20741