File-sharing worms have been terrorizing Peer-to-peer (P2P) systems in recent years. Existing defenses relying on users' individual recoveries or limiting users' file-sharing activities are ineffective. Automated patching tools such as Microsoft Windows Update and Symantec Security Update are currently the most popular vehicles for eliminating and containing Internet worms, but they are not necessarily the best fits for combating P2P file-sharing worms, which propagate within a relatively smaller community. In this paper, we propose a complementary P2P-tailored patching system which utilizes the existing file-sharing mechanisms to internally disseminate security patches to those participating peers in a timely and distributed fashion. Specifically, we examine the effectiveness of leveraging the file downloading or searching process to notify vulnerable end hosts of the surging worms and push corresponding security updates to these hosts. We show through in-depth analysis and extensive experiments that both methods are scalable and effective in combating existing P2P worms.