diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 1bfa29e1b28..1667d8093f1 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -5789,9 +5789,15 @@ mul_var(NumericVar *var1, NumericVar *var2, NumericVar *result,
 	 * to avoid normalizing carries immediately.
 	 *
 	 * maxdig tracks the maximum possible value of any dig[] entry; when this
-	 * threatens to exceed INT_MAX, we take the time to propagate carries. To
-	 * avoid overflow in maxdig itself, it actually represents the max
-	 * possible value divided by NBASE-1.
+	 * threatens to exceed INT_MAX, we take the time to propagate carries.
+	 * Furthermore, we need to ensure that overflow doesn't occur during the
+	 * carry propagation passes either.  The carry values could be as much as
+	 * INT_MAX/NBASE, so really we must normalize when digits threaten to
+	 * exceed INT_MAX - INT_MAX/NBASE.
+	 *
+	 * To avoid overflow in maxdig itself, it actually represents the max
+	 * possible value divided by NBASE-1, ie, at the top of the loop it is
+	 * known that no dig[] entry exceeds maxdig * (NBASE-1).
 	 */
 	dig = (int *) palloc0(res_ndigits * sizeof(int));
 	maxdig = 0;
@@ -5806,7 +5812,7 @@ mul_var(NumericVar *var1, NumericVar *var2, NumericVar *result,
 
 		/* Time to normalize? */
 		maxdig += var1digit;
-		if (maxdig > INT_MAX / (NBASE - 1))
+		if (maxdig > (INT_MAX - INT_MAX / NBASE) / (NBASE - 1))
 		{
 			/* Yes, do it */
 			carry = 0;
diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
index 9d6814564df..394cc72b645 100644
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -1309,6 +1309,33 @@ SELECT * FROM num_input_test;
      NaN
 (7 rows)
 
+--
+-- Test some corner cases for multiplication
+--
+select 4790999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+                                                                                     ?column?                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ 47909999999999999999999999999999999999999999999999999999999999999999999999999999999999985209000000000000000000000000000000000000000000000000000000000000000000000000000000000001
+(1 row)
+
+select 4789999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+                                                                                     ?column?                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ 47899999999999999999999999999999999999999999999999999999999999999999999999999999999999985210000000000000000000000000000000000000000000000000000000000000000000000000000000000001
+(1 row)
+
+select 4770999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+                                                                                     ?column?                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ 47709999999999999999999999999999999999999999999999999999999999999999999999999999999999985229000000000000000000000000000000000000000000000000000000000000000000000000000000000001
+(1 row)
+
+select 4769999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+                                                                                     ?column?                                                                                     
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ 47699999999999999999999999999999999999999999999999999999999999999999999999999999999999985230000000000000000000000000000000000000000000000000000000000000000000000000000000000001
+(1 row)
+
 --
 -- Test some corner cases for division
 --
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
index 1633e4c3752..5405ffadc79 100644
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -811,6 +811,18 @@ INSERT INTO num_input_test(n1) VALUES (' N aN ');
 
 SELECT * FROM num_input_test;
 
+--
+-- Test some corner cases for multiplication
+--
+
+select 4790999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+
+select 4789999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+
+select 4770999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+
+select 4769999999999999999999999999999999999999999999999999999999999999999999999999999999999999 * 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999;
+
 --
 -- Test some corner cases for division
 --