diff --git a/classes/comment.php b/classes/comment.php
index efe42e1..0726da4 100644
--- a/classes/comment.php
+++ b/classes/comment.php
@@ -170,7 +170,7 @@ public function save() {
         global $DB, $USER;
 
         $this->timemodified = time();
-        $this->content = html_to_text($this->content, 5000, false);
+        $this->content = clean_param(html_to_text($this->content, 5000, false), PARAM_TEXT);
 
         if ($this->id > 0) {
             $DB->update_record('board_comments', $this);