diff --git a/src/conf.c b/src/conf.c
index 41349ec1e..ef845dcde 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -1477,7 +1477,7 @@ int HAMLIB_API rig_set_conf(RIG *rig, hamlib_token_t token, const char *val)
 {
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
-    if (!rig || !rig->caps)
+    if (!rig || !rig->caps || !val)
     {
         return -RIG_EINVAL;
     }