The skb_gro_header_slow function in include/linux/netdevice.h in the Linux kernel before 2.6.39.4, when Generic Receive Offload (GRO) is enabled, resets certain fields in incorrect situations, which allows remote attackers to cause a denial of service (system crash) via crafted network traffic.
http://marc.info/?l=bugtraq&m=139447903326211&w=2
http://openwall.com/lists/oss-security/2011/07/28/13
http://openwall.com/lists/oss-security/2011/07/29/1
http://securitytracker.com/id?1025876
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.39.4
http://www.redhat.com/support/errata/RHSA-2011-1321.html