(ospf6d): Denial of service by decoding malformed Database Description packet headers

The ospf6lsaischanged function in ospf6lsa.c in the OSPFv3 implementation in ospf6d in Quagga before 0.99.19 allows remote attackers to cause a denial of service assertion failure and daemon exit via trailing zero values in the Link State Advertisement LSA header list of an IPv6 Database...