I have a simple circuit with a relay with a SSR. I am getting leakage measured using a multimeter of ~4v. Is there a way to eliminate the leak?
Firstly, Shock isn't due to voltage but due to current. check this

Now coming to the circuit. From your explanation, I am sure if the multimeter is connected to the load terminal of SSR or the input terminal

Assuming it's on the load terminal, even if the SSR is deactivated then the SSR load terminal will have some voltage at your terminal and you cannot judge an SSR using voltage. Typically, current flows when the voltage is zero across the SSR and this cannot be validated until there is a valid load for it

Try to googling for Datasheet of the SSR you have. It will specify about the leakage current of the SSR. That should be your judging criteria