Conn. Gen. Stat. § 52-75: Action by holder of mortgage or lien where grantee assumed the debt.

Whenever any real property encumbered by mortgage or lien is conveyed subject to the mortgage or lien and there is a provision in the conveyance that the grantee shall assume and pay the encumbrance, the holder of the mortgage or lien may, upon the nonpayment of the the encumbrance, maintain an action in his own name upon the grantee's promise, without obtaining an assignment thereof from the grantor of the property.