False routing announcements are a serious security problem, which can lead to widespread service disruptions in the Internet. A number of detection systems have been proposed and implemented recently, however, it takes time to detect attacks, notify operators, and stop false announcements. Thus detection systems should be complemented by a mitigation scheme that can protect data delivery before the attack is resolved. We propose such a mitigation scheme, QBGP, which decouples the propagation of a path and the adoption of a path for data forwarding. QBGP does not use suspicious paths to forward data traffic, but still propagates them in the routing system to facilitate attack detection. It can protect data delivery from routing announcements of false sub-prefixes, false origins, false nodes and false links. QBGP incurs overhead only when there are suspicious paths, which happen infrequently in real BGP traces. Results from large scale simulations and BGP trace analysis show that QBGP is light-weight yet effective, and it converges faster and incurs less overhead than Pretty Good BGP.