  Cayley hash functions are cryptographic hashes constructed from Cayley graphs
of groups. The hash function proposed by Shpilrain and Sosnovski (2016), based
on linear functions over a finite field, was proven insecure. This paper shows
that the proposal by Ghaffari and Mostaghim (2018) that uses the Shpilrain and
Sosnovski's hash in its construction is also insecure. We demonstrate its
security vulnerability by constructing collisions.
