diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
new file mode 100644
index 1bfa29e..4b39c7a
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -5792,9 +5792,13 @@ mul_var(NumericVar *var1, NumericVar *va
 	 * 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.
+	 *
+	 * Note that the carry propagation steps may carry as much as INT_MAX/NBASE
+	 * from one digit to the next, so we have to leave headroom for that as
+	 * well.
 	 */
 	dig = (int *) palloc0(res_ndigits * sizeof(int));
-	maxdig = 0;
+	maxdig = (INT_MAX / NBASE) / (NBASE - 1);
 
 	ri = res_ndigits - 1;
 	for (i1 = var1ndigits - 1; i1 >= 0; ri--, i1--)
@@ -5824,7 +5828,7 @@ mul_var(NumericVar *var1, NumericVar *va
 			}
 			Assert(carry == 0);
 			/* Reset maxdig to indicate new worst-case */
-			maxdig = 1 + var1digit;
+			maxdig = 1 + var1digit + (INT_MAX / NBASE) / (NBASE - 1);
 		}
 
 		/* Add appropriate multiple of var2 into the accumulator */
diff --git a/src/test/regress/expected/numeric.out b/src/test/regress/expected/numeric.out
new file mode 100644
index e6ee548..c1886fd
--- a/src/test/regress/expected/numeric.out
+++ b/src/test/regress/expected/numeric.out
@@ -1334,6 +1334,33 @@ SELECT * FROM num_input_test;
 (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
 --
 select 999999999999999999999::numeric/1000000000000000000000;
diff --git a/src/test/regress/sql/numeric.sql b/src/test/regress/sql/numeric.sql
new file mode 100644
index 982287c..49ec478
--- a/src/test/regress/sql/numeric.sql
+++ b/src/test/regress/sql/numeric.sql
@@ -822,6 +822,18 @@ INSERT INTO num_input_test(n1) VALUES ('
 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
 --