diff --git a/src/core/wee-hashtable.c b/src/core/wee-hashtable.c
index 5ba961f50..ba25da341 100644
--- a/src/core/wee-hashtable.c
+++ b/src/core/wee-hashtable.c
@@ -375,7 +375,7 @@ hashtable_get_item (struct t_hashtable *hashtable, const void *key,
     unsigned int key_hash;
     struct t_hashtable_item *ptr_item;
 
-    if (!hashtable)
+    if (!hashtable || !key)
         return NULL;
 
     key_hash = hashtable->callback_hash_key (hashtable, key);