diff --git a/src/libnm-glib-aux/nm-uuid.c b/src/libnm-glib-aux/nm-uuid.c
index 23f57f23aa..19b096670b 100644
--- a/src/libnm-glib-aux/nm-uuid.c
+++ b/src/libnm-glib-aux/nm-uuid.c
@@ -387,9 +387,15 @@ nm_uuid_generate_from_string_str(const char   *s,
                                  NMUuidType    uuid_type,
                                  const NMUuid *type_args)
 {
-    NMUuid uuid;
+    NMUuid        uuid;
+    const NMUuid *u;
+
+    u = nm_uuid_generate_from_string(&uuid, s, slen, uuid_type, type_args);
+
+    if (G_UNLIKELY(!u))
+        return nm_assert_unreachable_val(NULL);
+    nm_assert(u == &uuid);
 
-    nm_uuid_generate_from_string(&uuid, s, slen, uuid_type, type_args);
     return nm_uuid_unparse(&uuid, g_new(char, 37));
 }