diff --git a/mod/assignment/config.html b/mod/assignment/config.html
index 75e0faf72ee..ea2150b7842 100644
--- a/mod/assignment/config.html
+++ b/mod/assignment/config.html
@@ -1,4 +1,5 @@
 <form method="post" action="module.php" name="form">
+<input type="hidden" name="sesskey" value="<?php echo sesskey(); ?>" />
 
 <table cellpadding=9 cellspacing=0 >
 <tr valign=top>