diff --git a/nsupdate/main/templates/main/about.html b/nsupdate/main/templates/main/about.html
index 9fd6bc3..22cea33 100644
--- a/nsupdate/main/templates/main/about.html
+++ b/nsupdate/main/templates/main/about.html
@@ -47,7 +47,7 @@
                 {% blocktrans trimmed %}
                 Also, we have
                 <a href="http://nsupdateinfo.readthedocs.org/"
-                   title="Open docs in new window" target="_blank">documentation</a> &mdash;
+                   title="Open docs in new window" target="_blank" rel="noopener">documentation</a> &mdash;
                 there might be some interesting stuff for you in it that is
                 not visible or obvious on the user interface.
                 {% endblocktrans %}
diff --git a/nsupdate/templates/base.html b/nsupdate/templates/base.html
index 2a77e09..ecbde37 100644
--- a/nsupdate/templates/base.html
+++ b/nsupdate/templates/base.html
@@ -52,7 +52,7 @@
                         </li>
                         <li>
                             <a href="http://nsupdateinfo.readthedocs.org/"
-                               class="navbar-link" title="Open docs in new window" target="_blank"><i class="fa fa-eye fa-fw"></i> {% trans "Documentation" %}</a>
+                               class="navbar-link" title="Open docs in new window" target="_blank" rel="noopener"><i class="fa fa-eye fa-fw"></i> {% trans "Documentation" %}</a>
                         </li>
                     </ul>
                     <ul class="nav navbar-nav pull-right">
@@ -94,7 +94,7 @@
                             </ul>
                         </li>
                     </ul>
-                </div>
+                </div>_blac
             </div>
         </div>
         {% block header %}{% endblock %}