diff --git a/stack_gvisor.go b/stack_gvisor.go
index 80c78af..df6a2b2 100644
--- a/stack_gvisor.go
+++ b/stack_gvisor.go
@@ -153,7 +153,9 @@ func (t *GVisor) Start() error {
 }
 
 func (t *GVisor) Close() error {
-	t.endpoint.Attach(nil)
+	if t.endpoint != nil {
+		t.endpoint.Attach(nil)
+	}
 	t.stack.Close()
 	for _, endpoint := range t.stack.CleanupEndpoints() {
 		endpoint.Abort()
diff --git a/stack_mixed.go b/stack_mixed.go
index 03f887a..e7fa07f 100644
--- a/stack_mixed.go
+++ b/stack_mixed.go
@@ -261,7 +261,9 @@ func (m *Mixed) packetLoop() {
 }
 
 func (m *Mixed) Close() error {
-	m.endpoint.Attach(nil)
+	if m.endpoint != nil {
+		m.endpoint.Attach(nil)
+	}
 	m.stack.Close()
 	for _, endpoint := range m.stack.CleanupEndpoints() {
 		endpoint.Abort()