TWiki 4.0, 4.0.1, and 20010901 through 20040904 allows remote authenticated users with edit rights to cause a denial of service (infinite recursion leading to CPU and memory consumption) via INCLUDE by URL statements that form a loop, such as a page that includes itself.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25445
http://www.vupen.com/english/advisories/2006/1116
http://www.securityfocus.com/bid/17267
http://twiki.org/cgi-bin/view/Codev/SecurityAdvisoryDosAttackWithInclude