Halachafortoday says
“2) The only permissible relatives for a person to hug and kiss are a mother/father, son/daughter, grandson/granddaughter according to some Poskim and a sister below the age of 3 (or 7 according to the Chazon Ish). (See Aruch Hashulchan Even HaEzer Siman 21:10)
All other relatives (Uncles/Aunts, Sisters in law/brothers in law, cousins etc.) may not be touched, kissed or hugged, and all the Halachos of other females apply to them.”