diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 544a30d61..7065bcdcb 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -1302,6 +1302,7 @@ grub_cryptodisk_scan_device_real (const char *name,
 
   if (askpass)
     {
+      grub_memset (cargs->key_data, 0, cargs->key_len);
       cargs->key_len = 0;
       grub_free (cargs->key_data);
     }