Cisco 12000 with IOS 12.0 and line cards based on Engine 2 does not handle the "fragment" keyword in a compiled ACL (Turbo ACL) for packets that are sent to the router, which allows remote attackers to cause a denial of service via a flood of fragments.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7551
http://www.securityfocus.com/bid/3539