diff --git a/adminstuds.php b/adminstuds.php
index 8de758c..1cdff56 100644
--- a/adminstuds.php
+++ b/adminstuds.php
@@ -46,7 +46,7 @@ $inputService = new InputService();
 /* ---- */
 
 if (!empty($_GET['poll']) && strlen($_GET['poll']) === 24) {
-    $admin_poll_id = filter_input(INPUT_GET, 'poll', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => '/^[a-z0-9]+$/']]);
+    $admin_poll_id = filter_input(INPUT_GET, 'poll', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => POLL_REGEX]]);
     $poll_id = substr($admin_poll_id, 0, 16);
     $poll = $pollService->findById($poll_id);
 }
@@ -67,7 +67,7 @@ if (isset($_POST['update_poll_info'])) {
 
     // Update the right poll field
     if ($field == 'title') {
-        $title = filter_input(INPUT_POST, 'title', FILTER_DEFAULT);
+        $title = strip_tags($_POST['title']);
         if ($title) {
             $poll->title = $title;
             $updated = true;
@@ -79,13 +79,13 @@ if (isset($_POST['update_poll_info'])) {
             $updated = true;
         }
     } elseif ($field == 'comment') {
-        $comment = filter_input(INPUT_POST, 'comment', FILTER_DEFAULT);
+        $comment = strip_tags($_POST['comment']);
         if ($comment) {
             $poll->comment = $comment;
             $updated = true;
         }
     } elseif ($field == 'rules') {
-        $rules = filter_input(INPUT_POST, 'rules', FILTER_DEFAULT);
+        $rules = strip_tags($_POST['rules']);
         switch ($rules) {
             case 0:
                 $poll->active = false;
@@ -127,7 +127,7 @@ if (!empty($_POST['edit_vote'])) {
 
 if (!empty($_POST['save'])) { // Save edition of an old vote
     $editedVote = filter_input(INPUT_POST, 'save', FILTER_VALIDATE_INT);
-    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[012]$/']]);
+    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => CHOICE_REGEX]]);
 
     if (empty($editedVote)) {
         $message = new Message('danger', _('Something is going wrong...'));
@@ -146,8 +146,8 @@ if (!empty($_POST['save'])) { // Save edition of an old vote
         }
     }
 } elseif (isset($_POST['save'])) { // Add a new vote
-    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[a-z0-9_ -]+$/i']]);
-    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[012]$/']]);
+    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => NAME_REGEX]]);
+    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => CHOICE_REGEX]]);
 
     if (empty($name)) {
         $message = new Message('danger', _('Name is incorrect.'));
@@ -204,8 +204,8 @@ if (isset($_POST['confirm_remove_all_votes'])) {
 // -------------------------------
 
 if (isset($_POST['add_comment'])) {
-    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[a-z0-9_ -]+$/i']]);
-    $comment = filter_input(INPUT_POST, 'comment', FILTER_DEFAULT);
+    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => NAME_REGEX]]);
+    $comment = strip_tags($_POST['comment']);
 
     if (empty($name)) {
         $message = new Message('danger', _('Name is incorrect.'));
@@ -308,7 +308,7 @@ if (!empty($_POST['delete_column'])) {
 }
 
 // -------------------------------
-// Delete a slot
+// Add a slot
 // -------------------------------
 
 if (isset($_POST['add_slot'])) {
@@ -321,14 +321,14 @@ if (isset($_POST['add_slot'])) {
 }
 if (isset($_POST['confirm_add_slot'])) {
     if ($poll->format === 'D') {
-        $newdate = filter_input(INPUT_POST, 'newdate', FILTER_DEFAULT);
-        $newmoment = filter_input(INPUT_POST, 'newmoment', FILTER_DEFAULT);
+        $newdate = strip_tags($_POST['newdate']);
+        $newmoment = strip_tags($_POST['newmoment']);
 
         $ex = explode('/', $newdate);
         $result = $adminPollService->addSlot($poll_id, mktime(0, 0, 0, $ex[1], $ex[0], $ex[2]), $newmoment);
     } else {
-        $newslot = filter_input(INPUT_POST, 'choice', FILTER_DEFAULT);
-        $result = $adminPollService->addSlot($poll_id,$newslot, null);
+        $newslot = strip_tags($_POST['choice']);
+        $result = $adminPollService->addSlot($poll_id, $newslot, null);
     }
 
     if ($result) {
diff --git a/app/inc/constants.php.template b/app/inc/constants.php.template
index ca5db6a..d8faf34 100644
--- a/app/inc/constants.php.template
+++ b/app/inc/constants.php.template
@@ -55,6 +55,11 @@ $ALLOWED_LANGUAGES = [
     'de_DE' => 'Deutsch',
 ];
 
+// Regex
+const POLL_REGEX = '/^[a-z0-9]+$/';
+const CHOICE_REGEX = '/^[012]$/';
+const NAME_REGEX = '/^[ a-z0-9_ -]+$/i';
+
 // Path to logo
 const LOGOBANDEAU = '<relative path to the logo file>';
 
diff --git a/choix_autre.php b/choix_autre.php
index e9bd1d1..c16ed50 100644
--- a/choix_autre.php
+++ b/choix_autre.php
@@ -134,7 +134,7 @@ if (empty($_SESSION['form']->title) || empty($_SESSION['form']->admin_name) || (
             $_SESSION['form']->clearChoices();
             foreach ($_POST['choices'] as $c) {
                 if (!empty($c)) {
-                    $c = filter_var($c, FILTER_SANITIZE_STRING);
+                    $c = strip_tags($c);
                     $choice = new Choice($c);
                     $_SESSION['form']->addChoice($choice);
                 }
diff --git a/choix_date.php b/choix_date.php
index bfe0790..b94658f 100644
--- a/choix_date.php
+++ b/choix_date.php
@@ -140,7 +140,7 @@ if (!isset($_SESSION['form']->title) || !isset($_SESSION['form']->admin_name) ||
                     $schedules = $inputService->filterArray($_POST['horaires'.$i], FILTER_DEFAULT);
                     for($j = 0; $j < count($schedules); $j++) {
                         if (!empty($schedules[$j])) {
-                            $choice->addSlot($schedules[$j]);
+                            $choice->addSlot(strip_tags($schedules[$j]));
                         }
                     }
                 }
diff --git a/studs.php b/studs.php
index b04ce05..96b2360 100644
--- a/studs.php
+++ b/studs.php
@@ -53,7 +53,7 @@ $mailService = new MailService($config['use_smtp']);
 function sendUpdateNotification($poll, $mailService) {
     if ($poll->receiveNewVotes && !isset($_SESSION['mail_sent'][$poll->id])) {
 
-        $subject = '[' . NOMAPPLICATION . '] ' . _('Poll\'s participation') . ' : ' . html_entity_decode($poll->title, ENT_QUOTES, 'UTF-8');
+        $subject = '[' . NOMAPPLICATION . '] ' . _('Poll\'s participation') . ' : ' . $poll->title;
         $message = html_entity_decode('"$nom" ', ENT_QUOTES, 'UTF-8') .
             _('has filled a line.\nYou can find your poll at the link') . " :\n\n" .
             Utils::getUrlSondage($poll->admin_poll_id, true) . " \n\n" .
@@ -68,8 +68,8 @@ function sendUpdateNotification($poll, $mailService) {
 /* PAGE */
 /* ---- */
 
-if(!empty($_GET['poll'])) {
-    $poll_id = filter_input(INPUT_GET, 'poll', FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[a-z0-9]+$/']]);
+if (!empty($_GET['poll'])) {
+    $poll_id = filter_input(INPUT_GET, 'poll', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => POLL_REGEX]]);
     $poll = $pollService->findById($poll_id);
 }
 
@@ -94,7 +94,7 @@ if (!empty($_POST['edit_vote'])) {
 
 if (!empty($_POST['save'])) { // Save edition of an old vote
     $editedVote = filter_input(INPUT_POST, 'save', FILTER_VALIDATE_INT);
-    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[012]$/']]);
+    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => CHOICE_REGEX]]);
 
     if (empty($editedVote)) {
         $message = new Message('danger', _('Something is going wrong...'));
@@ -114,8 +114,8 @@ if (!empty($_POST['save'])) { // Save edition of an old vote
         }
     }
 } elseif (isset($_POST['save'])) { // Add a new vote
-    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[a-z0-9_ -]+$/i']]);
-    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[012]$/']]);
+    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => NAME_REGEX]]);
+    $choices = $inputService->filterArray($_POST['choices'], FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => CHOICE_REGEX]]);
 
     if (empty($name)) {
         $message = new Message('danger', _('Name is incorrect.'));
@@ -141,8 +141,8 @@ if (!empty($_POST['save'])) { // Save edition of an old vote
 // -------------------------------
 
 if (isset($_POST['add_comment'])) {
-    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options'=>['regexp'=>'/^[a-z0-9_ -]+$/i']]);
-    $comment = filter_input(INPUT_POST, 'comment', FILTER_DEFAULT);
+    $name = filter_input(INPUT_POST, 'name', FILTER_VALIDATE_REGEXP, ['options' => ['regexp' => NAME_REGEX]]);
+    $comment = strip_tags($_POST['comment']);
 
     if (empty($name)) {
         $message = new Message('danger', _('Name is incorrect.'));