The fib6_add_rt2node function in net/ipv6/ip6_fib.c in the IPv6 stack in the Linux kernel through 3.10.1 does not properly handle Router Advertisement (RA) messages in certain circumstances involving three routes that initially qualified for membership in an ECMP route set until a change occurred for one of the first two routes, which allows remote attackers to cause a denial of service (system crash) via a crafted sequence of messages.