diff --git a/executor/insert.go b/executor/insert.go
index 7b0758c7ff076..76197d22ea479 100644
--- a/executor/insert.go
+++ b/executor/insert.go
@@ -360,7 +360,7 @@ func (e *InsertExec) initEvalBuffer4Dup() {
 		evalBufferTypes = append(evalBufferTypes, &col.FieldType)
 	}
 	if extraLen > 0 {
-		evalBufferTypes = append(evalBufferTypes, e.SelectExec.base().retFieldTypes[numWritableCols:]...)
+		evalBufferTypes = append(evalBufferTypes, e.SelectExec.base().retFieldTypes[e.rowLen:]...)
 	}
 	for _, col := range e.Table.Cols() {
 		evalBufferTypes = append(evalBufferTypes, &col.FieldType)
@@ -369,7 +369,7 @@ func (e *InsertExec) initEvalBuffer4Dup() {
 		evalBufferTypes = append(evalBufferTypes, types.NewFieldType(mysql.TypeLonglong))
 	}
 	e.evalBuffer4Dup = chunk.MutRowFromTypes(evalBufferTypes)
-	e.curInsertVals = chunk.MutRowFromTypes(evalBufferTypes[numWritableCols:])
+	e.curInsertVals = chunk.MutRowFromTypes(evalBufferTypes[numWritableCols+extraLen:])
 	e.row4Update = make([]types.Datum, 0, len(evalBufferTypes))
 }
 
diff --git a/executor/insert_test.go b/executor/insert_test.go
index e6311a5a74ff8..2c790ccd1ddce 100644
--- a/executor/insert_test.go
+++ b/executor/insert_test.go
@@ -210,6 +210,36 @@ func (s *testSuite8) TestInsertOnDuplicateKey(c *C) {
 	c.Assert(tk.Se.AffectedRows(), Equals, uint64(2))
 	tk.MustQuery("select * from a").Check(testkit.Rows("2"))
 
+	// Test issue 28078.
+	// Use different types of columns so that there's likely to be error if the types mismatches.
+	tk.MustExec("drop table if exists a, b")
+	tk.MustExec("create table a(id int, a1 timestamp, a2 varchar(10), a3 float, unique(id))")
+	tk.MustExec("create table b(id int, b1 time, b2 varchar(10), b3 int)")
+	tk.MustExec("insert into a values (1, '2022-01-04 07:02:04', 'a', 1.1), (2, '2022-01-04 07:02:05', 'b', 2.2)")
+	tk.MustExec("insert into b values (2, '12:34:56', 'c', 10), (3, '01:23:45', 'd', 20)")
+	tk.MustExec("insert into a (id) select id from b on duplicate key update a.a2 = b.b2, a.a3 = 3.3")
+	c.Assert(tk.Se.AffectedRows(), Equals, uint64(3))
+	tk.MustQuery("select * from a").Check(testutil.RowsWithSep("/",
+		"1/2022-01-04 07:02:04/a/1.1",
+		"2/2022-01-04 07:02:05/c/3.3",
+		"3/<nil>/<nil>/<nil>"))
+	tk.MustExec("insert into a (id) select 4 from b where b3 = 20 on duplicate key update a.a3 = b.b3")
+	c.Assert(tk.Se.AffectedRows(), Equals, uint64(1))
+	tk.MustQuery("select * from a").Check(testutil.RowsWithSep("/",
+		"1/2022-01-04 07:02:04/a/1.1",
+		"2/2022-01-04 07:02:05/c/3.3",
+		"3/<nil>/<nil>/<nil>",
+		"4/<nil>/<nil>/<nil>"))
+	tk.MustExec("insert into a (a2, a3) select 'x', 1.2 from b on duplicate key update a.a2 = b.b3")
+	c.Assert(tk.Se.AffectedRows(), Equals, uint64(2))
+	tk.MustQuery("select * from a").Check(testutil.RowsWithSep("/",
+		"1/2022-01-04 07:02:04/a/1.1",
+		"2/2022-01-04 07:02:05/c/3.3",
+		"3/<nil>/<nil>/<nil>",
+		"4/<nil>/<nil>/<nil>",
+		"<nil>/<nil>/x/1.2",
+		"<nil>/<nil>/x/1.2"))
+
 	// reproduce insert on duplicate key update bug under new row format.
 	tk.MustExec(`drop table if exists t1`)
 	tk.MustExec(`create table t1(c1 decimal(6,4), primary key(c1))`)