diff --git a/netjsonconfig/backends/openvpn/converters.py b/netjsonconfig/backends/openvpn/converters.py
index 922b7f83f..5853e826b 100644
--- a/netjsonconfig/backends/openvpn/converters.py
+++ b/netjsonconfig/backends/openvpn/converters.py
@@ -24,7 +24,8 @@ def to_intermediate_loop(self, block, result, index=None):
         result['openvpn'].append(vpn)
         return result
 
-    def __intermediate_vpn(self, config, remove=[False, 0, '']):
+    def __intermediate_vpn(self, config, remove=None):
+        remove = remove or [False, 0, '']
         skip_keys = ['script_security', 'remote']
         delete_keys = []
         # allow server_bridge to be empty and still rendered