diff --git a/modules/indexer/issues/internal/qstring.go b/modules/indexer/issues/internal/qstring.go
index 8115fc904f..6b60b4c5f6 100644
--- a/modules/indexer/issues/internal/qstring.go
+++ b/modules/indexer/issues/internal/qstring.go
@@ -25,7 +25,7 @@ type Token struct {
 
 func (tk *Token) ParseIssueReference() (int64, error) {
 	term := tk.Term
-	if term[0] == '#' || term[0] == '!' {
+	if len(term) > 1 && (term[0] == '#' || term[0] == '!') {
 		term = term[1:]
 	}
 	return strconv.ParseInt(term, 10, 64)
diff --git a/modules/indexer/issues/internal/qstring_test.go b/modules/indexer/issues/internal/qstring_test.go
index a911b86e2f..835491707c 100644
--- a/modules/indexer/issues/internal/qstring_test.go
+++ b/modules/indexer/issues/internal/qstring_test.go
@@ -169,3 +169,35 @@ func TestIssueQueryString(t *testing.T) {
 		})
 	}
 }
+
+func TestToken_ParseIssueReference(t *testing.T) {
+	var tk Token
+	{
+		tk.Term = "123"
+		id, err := tk.ParseIssueReference()
+		require.NoError(t, err)
+		assert.Equal(t, int64(123), id)
+	}
+	{
+		tk.Term = "#123"
+		id, err := tk.ParseIssueReference()
+		require.NoError(t, err)
+		assert.Equal(t, int64(123), id)
+	}
+	{
+		tk.Term = "!123"
+		id, err := tk.ParseIssueReference()
+		require.NoError(t, err)
+		assert.Equal(t, int64(123), id)
+	}
+	{
+		tk.Term = "text"
+		_, err := tk.ParseIssueReference()
+		require.Error(t, err)
+	}
+	{
+		tk.Term = ""
+		_, err := tk.ParseIssueReference()
+		require.Error(t, err)
+	}
+}