The netfilter/iptables module in Linux before 2.6.8.1 allows remote attackers to cause a denial of service (kernel crash) or bypass firewall rules via crafted packets, which are not properly handled by the skb_checksum_help function.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.