The 802.11 standard is prone to selfish attacks performed by insiders, i.e., correctly authenticated stations. The recently released 802.11aa amendment is likewise prone to such attacks because the mechanisms which it provides can be selfishly configured by insiders to raise their QoS. In this paper, we present the first security analysis of 802.11aa by investigating selfish insider attacks against the intra-AC prioritization feature. Our analysis shows that 802.11aa is susceptible to already existing attacks as well as attacks previously not considered. Furthermore, our research shows the extent to which an attacker can benefit from these types of selfish behaviors. Therefore, we can identify which mechanisms should be augmented with countermeasures to protect 802.11aa networks from selfish attackers.