net/ipv6/addrconf.c in the IPv6 stack in the Linux kernel before 4.0 does not validate attempted changes to the MTU value, which allows context-dependent attackers to cause a denial of service (packet loss) via a value that is (1) smaller than the minimum compliant value or (2) larger than the MTU of an interface, as demonstrated by a Router Advertisement (RA) message that is not validated by a daemon, a different vulnerability than CVE-2015-0272.  NOTE: the scope of CVE-2015-0272 is limited to the NetworkManager product.