diff --git a/include/class.thread.php b/include/class.thread.php
index f7590175103e136e3a03962e4d5d38106b1f50af..87b0789c1aab0ec9ce37242252926781f179d1e6 100644
--- a/include/class.thread.php
+++ b/include/class.thread.php
@@ -1404,7 +1404,7 @@ class TextThreadBody extends ThreadBody {
         switch ($output) {
         case 'html':
             return '<div style="white-space:pre-wrap">'
-                .Format::clickableurls($this->body).'</div>';
+                .Format::clickableurls(Format::htmlchars($this->body)).'</div>';
         case 'email':
             return '<div style="white-space:pre-wrap">'.$this->body.'</div>';
         case 'pdf':