diff --git a/main/forum/viewforum.php b/main/forum/viewforum.php
index a584a33e7d..0486f53765 100755
--- a/main/forum/viewforum.php
+++ b/main/forum/viewforum.php
@@ -140,7 +140,7 @@ if (!empty($groupId)) {
     $interbreadcrumb[] = [
         'url' => $forumUrl.'viewforumcategory.php?forumcategory='.$current_forum_category['cat_id']
             .'&search='.Security::remove_XSS(urlencode($my_search)),
-        'name' => prepare4display($current_forum_category['cat_title']),
+        'name' => Security::remove_XSS(prepare4display($current_forum_category['cat_title'])),
     ];
     $interbreadcrumb[] = [
         'url' => '#',
@@ -375,7 +375,7 @@ if (api_is_allowed_to_edit(false, true) ||
 echo '</div>';
 
 /* Display */
-$titleForum = $current_forum['forum_title'];
+$titleForum = Security::remove_XSS($current_forum['forum_title']);
 $descriptionForum = $current_forum['forum_comment'];
 $iconForum = Display::return_icon(
     'forum_yellow.png',
@@ -440,7 +440,7 @@ if (is_array($threads)) {
             $linkPostForum = '<a href="viewthread.php?'.api_get_cidreq().'&forum='.$my_forum
                 ."&thread={$row['thread_id']}&search="
                 .Security::remove_XSS(urlencode($my_search)).'">'
-                .$row['thread_title'].'</a>';
+                .Security::remove_XSS($row['thread_title']).'</a>';
             $html = '';
             $html .= '<div class="panel panel-default forum '.($row['thread_sticky'] ? 'sticky' : '').'">';
             $html .= '<div class="panel-body">';
diff --git a/main/forum/viewforumcategory.php b/main/forum/viewforumcategory.php
index 64708411a1..e7273d720a 100755
--- a/main/forum/viewforumcategory.php
+++ b/main/forum/viewforumcategory.php
@@ -126,8 +126,6 @@ echo $html;
 
 $logInfo = [
     'tool' => TOOL_FORUM,
-    'tool_id' => 0,
-    'tool_id_detail' => 0,
     'action' => $action,
     'info' => isset($_GET['content']) ? $_GET['content'] : '',
 ];
@@ -181,7 +179,7 @@ if ($action != 'add') {
 
     $forum_categories_list = [];
     $forumId = $forum_category['cat_id'];
-    $forumTitle = $forum_category['cat_title'];
+    $forumTitle = Security::remove_XSS($forum_category['cat_title']);
     $linkForumCategory = 'viewforumcategory.php?'.api_get_cidreq().'&forumcategory='.strval(intval($forumId));
     $descriptionCategory = $forum_category['cat_comment'];
     $icoCategory = Display::return_icon(
@@ -271,15 +269,12 @@ if ($action != 'add') {
                 // you are teacher => show forum
 
                 if (api_is_allowed_to_edit(false, true)) {
-                    //echo 'teacher';
                     $show_forum = true;
                 } else {
                     // you are not a teacher
-                    //echo 'student';
                     // it is not a group forum => show forum
                     // (invisible forums are already left out see get_forums function)
                     if ($forum['forum_of_group'] == '0') {
-                        //echo '-gewoon forum';
                         $show_forum = true;
                     } else {
                         // it is a group forum
@@ -287,16 +282,13 @@ if ($action != 'add') {
                         // it is a group forum but it is public => show
                         if ($forum['forum_group_public_private'] == 'public') {
                             $show_forum = true;
-                        //echo '-publiek';
                         } else {
                             // it is a group forum and it is private
                             //echo '-prive';
                             // it is a group forum and it is private but the user is member of the group
                             if (in_array($forum['forum_of_group'], $groups_of_user)) {
-                                //echo '-is lid';
                                 $show_forum = true;
                             } else {
-                                //echo '-is GEEN lid';
                                 $show_forum = false;
                             }
                         }
@@ -360,14 +352,14 @@ if ($action != 'add') {
                     $html .= '<div class="col-md-9">';
                     $iconForum = Display::return_icon(
                         'forum_yellow.png',
-                        get_lang($forum_category['cat_title']),
+                        Security::remove_XSS(get_lang($forum_category['cat_title'])),
                         null,
                         ICON_SIZE_MEDIUM
                     );
 
                     $linkForum = Display::tag(
                         'a',
-                        $forum['forum_title'].$session_displayed,
+                        Security::remove_XSS($forum['forum_title']).$session_displayed,
                         [
                             'href' => 'viewforum.php?'.api_get_cidreq(true, false)."&gidReq={$forum['forum_of_group']}&forum={$forum['forum_id']}&search=".Security::remove_XSS(urlencode(isset($_GET['search']) ? $_GET['search'] : '')),
                             'class' => empty($forum['visibility']) ? 'text-muted' : null,
@@ -382,7 +374,7 @@ if ($action != 'add') {
                     );
                     $html .= Display::tag(
                         'p',
-                        strip_tags($forum['forum_comment']),
+                        Security::remove_XSS(strip_tags($forum['forum_comment'])),
                         [
                             'class' => 'description',
                         ]
diff --git a/main/template/default/forum/list.tpl b/main/template/default/forum/list.tpl
index 46ff57ea13..1916651042 100644
--- a/main/template/default/forum/list.tpl
+++ b/main/template/default/forum/list.tpl
@@ -47,7 +47,7 @@
 
             {% if fold_forum_categories %}
                 {% set panel_icon %}
-                    <a href="{{ item.url }}" title="{{ item.title }}">
+                    <a href="{{ item.url }}" title="{{ item.title | remove_xss }}">
                         <span class="open">{{ 'forum_blue.png'|img(32) }}</span>
                     </a>
                 {% endset %}
@@ -62,7 +62,8 @@
                 {% set panel_title %}
                     <a href="{{ item.url }}" title="{{ item.title }}">
                         <span class="open">{{ 'forum_blue.png'|img(32) }}</span>
-                        {{ item.title }}{{ item.icon_session }}
+                        {{ item.title | remove_xss }}
+                        {{ item.icon_session }}
                     </a>
                     {% for category_language_item in category_language_array %}
                         <span class="flag-icon flag-icon-{{ languages[category_language_item | lower] }}"></span>
@@ -106,7 +107,13 @@
                                         </div>
                                         <h3 class="title">
                                             {{ 'forum_yellow.png'|img(32) }}
-                                            <a href="{{ subitem.url }}" title="{{ subitem.title }}" class="{{ subitem.visibility != '1' ? 'text-muted': '' }}">{{ subitem.title }}</a>
+                                            <a
+                                                href="{{ subitem.url }}"
+                                                title="{{ subitem.title | remove_xss }}"
+                                                class="{{ subitem.visibility != '1' ? 'text-muted': '' }}"
+                                            >
+                                                {{ subitem.title | remove_xss }}
+                                            </a>
                                             {% if subitem.forum_of_group != 0 %}
                                                 <a class="forum-goto" href="../group/group_space.php?{{ _p.web_cid_query }}&gidReq={{ subitem.forum_of_group }}">
                                                     {{ "forum.png"|img(22) }} {{ "GoTo"|get_lang }} {{ subitem.forum_group_title }}
@@ -124,16 +131,16 @@
                                             </div>
                                         {% endif %}
                                         <div class="description">
-                                            {{ subitem.description }}
+                                            {{ subitem.description | remove_xss }}
                                         </div>
 
                                         {{ subitem.last_post_text }}
-
                                         {{ subitem.alert }}
+
                                         {% if subitem.moderation is not empty %}
                                             <span class="label label-warning">
-                                        {{ "PostsPendingModeration"|get_lang }}: {{ subitem.moderation }}
-                                    </span>
+                                                {{ "PostsPendingModeration"|get_lang }}: {{ subitem.moderation }}
+                                            </span>
                                         {% endif %}
                                     </div>
                                 </div>