Oracle SQL - Update Table Value By Matching Columns

I have two table and trying to update tableA with data from tableB but gives an error. My TableA has columns - colA,colB,colC,colX and table B has columns - colA,colB,colX. Sample data looks like this:

tableA:
XXYY, local,3/19,48
XXYY,ixc,3/19,24
XXYYlocal,3/20,48
XXYY,local,3/21,48

Table B:
XXYY,local,48
XXYY,ixc,24
PPQQ,local,72

this is the query I wrote
update tableA a
set (a.colX)=(select (b.colX) from tableB b where a.colA=b.colA and a.colB=b.colB);

When i run it gives this error:single row subquery returns more than one row.

tableB has only 1 value for colX for each colA,colB record but tableA has mutiple colA and colB repeated but for all of thsoe in table A i want to update the tableB.colX value for matching colA and colB.