In order to ensure and enforce endpoint security, Network Access Control (NAC) is attracting considerable interest from the research community. Most NAC architectures are based on 802.1x, EAP (Extensible Authentication Protocol), EAPoL (EAP over LAN) 802.11i, 802.11w, and RADIUS (Remote Authentication Dial-In User Service) protocols. Unprotected management and control frames in some of above protocols lead to several attacks. Eliminating flaws completely in design of each protocol is a challenge. These flaws help malicious user and infected endpoint to intrude into the NAC architecture to make damage into it. Many researches have been carried out to address this issue. In this paper, we have made an attempt to explain attacks in above protocols and present a survey and analysis of different solution approaches proposed by researchers. The affect of vulnerability and attack of above protocols in NAC is also discussed. The finding of this review will provide useful insights into the vulnerabilities, attacks in above protocols, and their proposed solutions with issues, which may create a research scope for strengthening security in NAC.