diff --git a/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_bool.go b/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_bool.go
index 46ed43836f2..e5a01805b02 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_bool.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_bool.go
@@ -39,6 +39,9 @@ func NewMapStringBool(m *map[string]bool) *MapStringBool {
 
 // String implements github.com/spf13/pflag.Value
 func (m *MapStringBool) String() string {
+	if m == nil || m.Map == nil {
+		return ""
+	}
 	pairs := []string{}
 	for k, v := range *m.Map {
 		pairs = append(pairs, fmt.Sprintf("%s=%t", k, v))
diff --git a/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_string.go b/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_string.go
index 00c550b0499..129470b3c2f 100644
--- a/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_string.go
+++ b/staging/src/k8s.io/apiserver/pkg/util/flag/map_string_string.go
@@ -50,6 +50,9 @@ func NewMapStringStringNoSplit(m *map[string]string) *MapStringString {
 
 // String implements github.com/spf13/pflag.Value
 func (m *MapStringString) String() string {
+	if m == nil || m.Map == nil {
+		return ""
+	}
 	pairs := []string{}
 	for k, v := range *m.Map {
 		pairs = append(pairs, fmt.Sprintf("%s=%s", k, v))