Heap-based buffer overflow in Squid before 2.4 STABLE4, and Squid 2.5 and 2.6 until March 12, 2002 distributions, allows remote attackers to cause a denial of service, and possibly execute arbitrary code, via compressed DNS responses.
http://www.squid-cache.org/Advisories/SQUID-2002_2.txt
http://www.securityfocus.com/bid/4363
http://www.linux-mandrake.com/en/security/2002/MDKSA-2002-027.php
http://www.iss.net/security_center/static/8628.php