Race condition in the Neighbor Discovery (ND) protocol implementation in Cisco IOS and IOS XE allows remote attackers to cause a denial of service via a flood of Router Solicitation messages on the local network, aka Bug ID CSCuo67770.
Concurrent Execution using Shared Resource with Improper Synchronization The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.