squid_redirect script in adzapper before 2006-01-29 allows remote attackers to cause a denial of service (CPU consumption) via a URL with a large number of trailing / (forward slashes), which might produce inefficient regular expressions.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24640
http://www.vupen.com/english/advisories/2006/0491
http://www.securityfocus.com/bid/16558
http://www.debian.org/security/2006/dsa-966
http://secunia.com/advisories/18777
http://secunia.com/advisories/18771
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=350308
http://bugs.debian.org/cgi-bin/bugreport.cgi/squid_redirect.diff?bug=350308%3Bmsg=5%3Batt=1