diff --git a/htdocs/core/actions_linkedfiles.inc.php b/htdocs/core/actions_linkedfiles.inc.php
index ad9ca441e8a..86d4e923131 100644
--- a/htdocs/core/actions_linkedfiles.inc.php
+++ b/htdocs/core/actions_linkedfiles.inc.php
@@ -36,8 +36,19 @@ if (GETPOST('uploadform', 'int') && empty($_POST) && empty($_FILES)) {
 	die;
 }
 
+if ((GETPOST('sendit', 'alpha')
+	|| GETPOST('linkit', 'restricthtml')
+	|| ($action == 'confirm_deletefile' && $confirm == 'yes')
+	|| ($action == 'confirm_updateline' && GETPOST('save', 'alpha') && GETPOST('link', 'alpha'))
+	|| ($action == 'renamefile' && GETPOST('renamefilesave', 'alpha'))) && empty($permissiontoadd)) {
+	dol_syslog('The file actions_linkedfiles.inc.php was included but paramater $permissiontoadd as not set before.');
+	print 'The file actions_linkedfiles.inc.php was included but paramater $permissiontoadd as not set before.';
+	die;
+}
+
+
 // Submit file/link
-if (GETPOST('sendit', 'alpha') && !empty($conf->global->MAIN_UPLOAD_DOC) && (!isset($permissiontoadd) || $permissiontoadd)) {
+if (GETPOST('sendit', 'alpha') && !empty($conf->global->MAIN_UPLOAD_DOC) && !empty($permissiontoadd)) {
 	if (!empty($_FILES)) {
 		if (is_array($_FILES['userfile']['tmp_name'])) {
 			$userfiles = $_FILES['userfile']['tmp_name'];
@@ -75,7 +86,7 @@ if (GETPOST('sendit', 'alpha') && !empty($conf->global->MAIN_UPLOAD_DOC) && (!is
 			}
 		}
 	}
-} elseif (GETPOST('linkit', 'restricthtml') && !empty($conf->global->MAIN_UPLOAD_DOC) && (!isset($permissiontoadd) || $permissiontoadd)) {
+} elseif (GETPOST('linkit', 'restricthtml') && !empty($conf->global->MAIN_UPLOAD_DOC) && !empty($permissiontoadd)) {
 	$link = GETPOST('link', 'alpha');
 	if ($link) {
 		if (substr($link, 0, 7) != 'http://' && substr($link, 0, 8) != 'https://' && substr($link, 0, 7) != 'file://' && substr($link, 0, 7) != 'davs://') {
@@ -87,7 +98,7 @@ if (GETPOST('sendit', 'alpha') && !empty($conf->global->MAIN_UPLOAD_DOC) && (!is
 
 
 // Delete file/link
-if ($action == 'confirm_deletefile' && $confirm == 'yes' && (!isset($permissiontoadd) || $permissiontoadd)) {
+if ($action == 'confirm_deletefile' && $confirm == 'yes' && !empty($permissiontoadd)) {
 	$urlfile = GETPOST('urlfile', 'alpha', 0, null, null, 1); // Do not use urldecode here ($_GET and $_REQUEST are already decoded by PHP).
 	if (GETPOST('section', 'alpha')) {
 		// For a delete from the ECM module, upload_dir is ECM root dir and urlfile contains relative path from upload_dir
@@ -158,7 +169,7 @@ if ($action == 'confirm_deletefile' && $confirm == 'yes' && (!isset($permissiont
 			exit;
 		}
 	}
-} elseif ($action == 'confirm_updateline' && GETPOST('save', 'alpha') && GETPOST('link', 'alpha') && (!isset($permissiontoadd) || $permissiontoadd)) {
+} elseif ($action == 'confirm_updateline' && GETPOST('save', 'alpha') && GETPOST('link', 'alpha') && !empty($permissiontoadd)) {
 	require_once DOL_DOCUMENT_ROOT.'/core/class/link.class.php';
 	$langs->load('link');
 	$link = new Link($db);
@@ -176,7 +187,7 @@ if ($action == 'confirm_deletefile' && $confirm == 'yes' && (!isset($permissiont
 	} else {
 		//error fetching
 	}
-} elseif ($action == 'renamefile' && GETPOST('renamefilesave', 'alpha') && (!isset($permissiontoadd) || $permissiontoadd)) {
+} elseif ($action == 'renamefile' && GETPOST('renamefilesave', 'alpha') && !empty($permissiontoadd)) {
 	// For documents pages, upload_dir contains already path to file from module dir, so we clean path into urlfile.
 	if (!empty($upload_dir)) {
 		$filenamefrom = dol_sanitizeFileName(GETPOST('renamefilefrom', 'alpha'), '_', 0); // Do not remove accents