Conn. Gen. Stat. § 47-14e: Mortgage or lease by joint tenants.

A mortgage or lease executed by all of the joint tenants does not sever the joint tenancy but is valid according to its terms against the joint tenants and the survivor or survivors of them. A mortgage or lease executed by less than all of the joint tenants is a severance only to the extent that, upon the death of any joint tenant joining in the mortgage or lease, the mortgage or lease will continue to encumber the interest accruing to the surviving joint tenant or tenants by reason of that death.