diff --git a/htdocs/comm/action/card.php b/htdocs/comm/action/card.php
index e44e5c3a973..0199bebc01e 100644
--- a/htdocs/comm/action/card.php
+++ b/htdocs/comm/action/card.php
@@ -831,7 +831,7 @@ if ($action == 'create')
 	print '<input type="hidden" name="token" value="'.newToken().'">';
 	print '<input type="hidden" name="action" value="add">';
 	print '<input type="hidden" name="donotclearsession" value="1">';
-	if ($backtopage) print '<input type="hidden" name="backtopage" value="'.($backtopage != '1' ? $backtopage : $_SERVER["HTTP_REFERER"]).'">';
+	if ($backtopage) print '<input type="hidden" name="backtopage" value="'.($backtopage != '1' ? $backtopage : htmlentities($_SERVER["HTTP_REFERER"])).'">';
 	if (empty($conf->global->AGENDA_USE_EVENT_TYPE)) print '<input type="hidden" name="actioncode" value="'.dol_getIdFromCode($db, 'AC_OTH', 'c_actioncomm').'">';
 
 	if (GETPOST("actioncode", 'aZ09') == 'AC_RDV') print load_fiche_titre($langs->trans("AddActionRendezVous"), '', 'title_agenda');
@@ -1232,7 +1232,7 @@ if ($id > 0)
 		print '<input type="hidden" name="action" value="update">';
 		print '<input type="hidden" name="id" value="'.$id.'">';
 		print '<input type="hidden" name="ref_ext" value="'.$object->ref_ext.'">';
-		if ($backtopage) print '<input type="hidden" name="backtopage" value="'.($backtopage != '1' ? $backtopage : $_SERVER["HTTP_REFERER"]).'">';
+		if ($backtopage) print '<input type="hidden" name="backtopage" value="'.($backtopage != '1' ? $backtopage : htmlentities($_SERVER["HTTP_REFERER"])).'">';
 		if (empty($conf->global->AGENDA_USE_EVENT_TYPE)) print '<input type="hidden" name="actioncode" value="'.$object->type_code.'">';
 
 		dol_fiche_head($head, 'card', $langs->trans("Action"), 0, 'action');
diff --git a/htdocs/public/error-401.php b/htdocs/public/error-401.php
index d6a6ed548ff..ac921fc9f78 100644
--- a/htdocs/public/error-401.php
+++ b/htdocs/public/error-401.php
@@ -21,7 +21,7 @@
     Sorry. You are not allowed to access this resource.
 
     <br>
-    <?php print isset($_SERVER["HTTP_REFERER"])?'You come from '.$_SERVER["HTTP_REFERER"].'.':''; ?>
+    <?php print isset($_SERVER["HTTP_REFERER"])?'You come from '.htmlentities($_SERVER["HTTP_REFERER"]).'.':''; ?>
 
     <hr>
 
diff --git a/htdocs/public/error-404.php b/htdocs/public/error-404.php
index 36547d26704..34a4ac03e9e 100644
--- a/htdocs/public/error-404.php
+++ b/htdocs/public/error-404.php
@@ -21,7 +21,7 @@
     You requested a website or a page that does not exists.
 
     <br>
-    <?php print isset($_SERVER["HTTP_REFERER"])?'You come from '.$_SERVER["HTTP_REFERER"].'.':''; ?>
+    <?php print isset($_SERVER["HTTP_REFERER"])?'You come from '.htmlentities($_SERVER["HTTP_REFERER"]).'.':''; ?>
 
     <hr>