diff --git a/packages/ns-api/files/misc/wireguard-migrate.py b/packages/ns-api/files/misc/wireguard-migrate.py
index b1901d734..76784695b 100644
--- a/packages/ns-api/files/misc/wireguard-migrate.py
+++ b/packages/ns-api/files/misc/wireguard-migrate.py
@@ -7,10 +7,12 @@
 
 # this script is supposed to be run by the 99-ns-api.wireguard uci defaults
 
+import ipaddress
+
 from euci import EUci
 
 
-def main():
+def migrate_old():
     e_uci = EUci()
     wireguard_sections = []
     for wg_id in e_uci.get("network"):
@@ -39,5 +41,29 @@ def main():
     e_uci.commit("network")
 
 
+def fix_addresses():
+    """Fix addresses without CIDR notation."""
+    e_uci = EUci()
+    for wg_id in e_uci.get("network"):
+        if e_uci.get("network", wg_id, "proto", dtype=str, default="") == "wireguard":
+            addresses = e_uci.get("network", wg_id, "addresses", dtype=str, default="", list=True)
+            fixed_addresses = []
+            for address in addresses:
+                if "/" not in address:
+                    try:
+                        vpn_network = e_uci.get(
+                            "network", wg_id, "ns_network", dtype=str, default=""
+                        )
+                        interface_network = ipaddress.IPv4Network(vpn_network)
+                        first_address = str(list(interface_network.hosts())[0])
+                        fixed_addresses.append(first_address + "/" + str(interface_network.prefixlen))
+                    except Exception:
+                        fixed_addresses.append(address)
+            e_uci.set("network", wg_id, "addresses", fixed_addresses)
+
+    e_uci.save("network")
+
+
 if __name__ == "__main__":
-    main()
+    migrate_old()
+    fix_addresses()
diff --git a/packages/ns-api/files/ns.wireguard b/packages/ns-api/files/ns.wireguard
index 59c193266..9f7471114 100644
--- a/packages/ns-api/files/ns.wireguard
+++ b/packages/ns-api/files/ns.wireguard
@@ -276,7 +276,7 @@ def add_server(args):
     e_uci.set('network', instance, 'listen_port', args['listen_port'])
     interface_network = ipaddress.IPv4Network(args['network'])
     first_ip = str(list(interface_network.hosts())[0])
-    e_uci.set('network', instance, 'addresses', [first_ip])
+    e_uci.set('network', instance, 'addresses', [first_ip + '/'+ str(interface_network.prefixlen)])
     e_uci.set('network', instance, 'ns_network', args['network'])
     if 'mtu' in args:
         e_uci.set('network', instance, 'mtu', args['mtu'])
@@ -312,7 +312,7 @@ def edit_server(args):
     e_uci.set('network', args['instance'], 'listen_port', args['listen_port'])
     interface_network = ipaddress.IPv4Network(args['network'])
     first_ip = str(list(interface_network.hosts())[0])
-    e_uci.set('network', args['instance'], 'addresses', [first_ip])
+    e_uci.set('network', args['instance'], 'addresses', [first_ip + '/'+ str(interface_network.prefixlen)])
     e_uci.set('network', args['instance'], 'ns_network', args['network'])
     if 'mtu' in args and args['mtu'] != '':
         e_uci.set('network', args['instance'], 'mtu', args['mtu'])