Cisco 12000 with IOS 12.0 and line cards based on Engine 2 does not properly handle the implicit "deny ip any any" rule in an outgoing ACL when the ACL contains exactly 448 entries, which can allow some outgoing packets to bypass access restrictions.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7553
http://www.securityfocus.com/bid/3536