Certificateless signature scheme provides the solution of key escrow problem inherit in ID based public key cryptography. Aggregate signature allows aggregating of n signature in one single short signature which is very efficient in ad-hoc networks, PDA, mobile computation and more. A certificateless aggregate signature scheme solves not only the certification problem and key escrow problem but also done aggregation of n user's signatures. Recently, Deng et al proposed a certificateless aggregate signature scheme in “Concurrency and Computation: Practice and Experience” [doi: 10.1002/cpe.3551] in 2015 and claims that it is unforgeable under some concrete attacks but during security analysis we found it is insecure by some concrete attacks. In this paper, we show that proposed scheme is forged by universal adversary.