diff -r dec07877fd39 -r fcc5e2f0befd src/cm/templates/site/text_history.html
--- a/src/cm/templates/site/text_history.html	Fri May 18 00:07:32 2012 +0200
+++ b/src/cm/templates/site/text_history.html	Sat May 19 10:21:54 2012 +0200
@@ -62,7 +62,7 @@
     {% endif %}
 </ul>
 
-<form id="compare_form" action="." method="post">
+<form id="compare_form" action="." method="post">{% csrf_token %}
 
 <input name="compare" id="compare_button" type="submit" value="{% blocktrans %}Compare selected versions{% endblocktrans %}"/>