Unspecified vulnerability in func_topic_threaded.php (aka threaded view mode) in Invision Power Board (IPB) before 2.1.7 21013.60810.s allows remote attackers to "access posts outside the topic."
https://euvd.enisa.europa.eu/vulnerability/EUVD-2006-4145
http://www.vupen.com/english/advisories/2006/3260