diff --git a/src/add-ons/kernel/drivers/disk/scsi/scsi_cd/scsi_cd.cpp b/src/add-ons/kernel/drivers/disk/scsi/scsi_cd/scsi_cd.cpp
index f5873ff361..ccb707e78e 100644
--- a/src/add-ons/kernel/drivers/disk/scsi/scsi_cd/scsi_cd.cpp
+++ b/src/add-ons/kernel/drivers/disk/scsi/scsi_cd/scsi_cd.cpp
@@ -369,7 +369,7 @@ get_set_volume(cd_driver_info *info, scsi_volume *volume, bool set)
 	if (buffer == NULL)
 		return B_NO_MEMORY;
 
-	memset(buffer, -1, sizeof(buffer));
+	memset(buffer, -1, len);
 
 	cmd.allocation_length = len;