action_public/search.php in Invision Power Board (IPB) 2.1.x and 2.0.x before 20060425 allows remote attackers to execute arbitrary PHP code via a search with a crafted value of the lastdate parameter, which alters the behavior of a regular expression to add a "#e" (execute) modifier.
https://exchange.xforce.ibmcloud.com/vulnerabilities/26070
http://www.vupen.com/english/advisories/2006/1534
http://www.securityfocus.com/bid/17695
http://www.securityfocus.com/archive/1/439607/100/0/threaded
http://www.securityfocus.com/archive/1/432451/100/0/threaded
http://www.securityfocus.com/archive/1/432226/100/0/threaded
http://www.securityfocus.com/archive/1/431990/100/0/threaded
http://securityreason.com/securityalert/796