diff --git a/src/libnm-core-impl/nm-setting-ip-config.c b/src/libnm-core-impl/nm-setting-ip-config.c
index 43ce5c6902..83b38b2be3 100644
--- a/src/libnm-core-impl/nm-setting-ip-config.c
+++ b/src/libnm-core-impl/nm-setting-ip-config.c
@@ -6021,6 +6021,7 @@ set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *ps
         priv->dhcp_timeout = g_value_get_int(value);
         break;
     case PROP_DHCP_IAID:
+        g_free(priv->dhcp_iaid);
         priv->dhcp_iaid = g_value_dup_string(value);
         break;
     case PROP_DHCP_HOSTNAME_FLAGS: