Race condition in ebtables netfilter module (ebtables.c) in Linux 2.6, when running on an SMP system that is operating under a heavy load, might allow remote attackers to cause a denial of service (crash) via a series of packets that cause a value to be modified after it has been read but before it has been locked.
Ubuntu Security Notice USN-199-1 - Multiple vulnerabilities exist in both linux-source-2.6.10 and linux-source-2.6.8. These include race conditions and denial of service flaws.