Does this leave me open to exploits?

So partway through making a game, i was advised to use replication to reduce lag. I figured this out after a little while and am ready to impliment this into my game. But the problem is this would make me have to keep all the games attacks and moves on the client which screams red flags to me. Would this leave my game more open to exploits and game stealing and what could i do to reduce the risk?

Using replication can always leave games open to easy stealing and exploits. I recommend you don't use it.