Djibouti, officially the Republic of Djibouti, is a country located in the Horn of Africa. It is bordered by Eritrea in the north, Ethiopia in the west and south, and Somalia in the southeast. The remainder of the border is formed by the Red Sea and the Gulf of Aden at the east.
Eritrea, on the Horn of Africa, also borders the Gulf of Aden.
The statement only discusses the coastal borders of Djibouti.  There is no way to know, from this statement, if Eritrea also has a border touching the Gulf of Aden.