HAS-V is a cryptographic hash function which processes 1024-bit message blocks and produces a hash value of variable length. The design of the hash function is based on design principles of the MD4 family. Recently, weaknesses have been shown in members of this family. Therefore, the analysis of the HAS-V hash function is of great interest. To the best of our knowledge this is the first article that investigates the security of the HAS-V hash function. In this article, we point out several structural weaknesses in HAS-V which lead to pseudo-collision attacks on HAS-V with tailored output. Furthermore, we show that (second) preimages can be found for HAS-V with a complexity of about 2162 hash computations.