Multiple Cisco products are affected by a vulnerability involving the Open Shortest Path First (OSPF) Routing Protocol Link State Advertisement (LSA) database. This vulnerability could allow an unauthenticated attacker to take full control of the OSPF Autonomous System (AS) domain routing table, blackhole traffic, and intercept traffic. The attacker could trigger this vulnerability by injecting crafted OSPF packets. Successful exploitation could cause flushing of the routing table on a targeted router, as well as propagation of the crafted OSPF LSA type 1 update throughout the OSPF AS domain. To exploit this vulnerability, an attacker must accurately determine certain parameters within the LSA database on the target router. This vulnerability can only be triggered by sending crafted unicast or multicast LSA type 1 packets. No other LSA type packets can trigger this vulnerability. OSPFv3 is not affected by this vulnerability. Fabric Shortest Path First (FSPF) protocol is not affected by this vulnerability. Cisco has confirmed the vulnerability in a security advisory and has released software updates.