a cd

I assume from your question that your mother died without a will and without any other property?  The CD is controlled by the terms of the contract your mother had with the bank that issued the CD.  Generally, if the bank does not hear from the owner by the due date, the bank will roll the CD over into a new CD of like terms as the old CD.  If you name was not on the CD as an owner or a beneficiary, then you will need to open and estate for your mother to obtain the power you need to redeem the CD.  You will have to follow the rules of estate administration if you are placed in charge of your mother's estate.  You should visit the probate court in the county where your mother resided to get more information.