Recently, Xiong et al. and Selvi et al. proposed a certificateless signature scheme secure in the standard model and a certificateless multi-receiver signcryption scheme secure in the random oracle model, respectively. In this paper, we show that they are insecure against malicious-butpassive KGC attacks. More specifically, the former does not achieve unforgeability and the latter does not satisfy confidentiality against type II adversaries.