diff --git a/blocks/rss_client/viewfeed.php b/blocks/rss_client/viewfeed.php
index 1c287d703c5..26451d6b742 100644
--- a/blocks/rss_client/viewfeed.php
+++ b/blocks/rss_client/viewfeed.php
@@ -84,15 +84,16 @@ if (!empty($rssrecord->preferredtitle)) {
     $feedtitle =  $rss->get_title();
 }
 echo '<table align="center" width="50%" cellspacing="1">'."\n";
-echo '<tr><td colspan="2"><strong>'. $feedtitle .'</strong></td></tr>'."\n";
+echo '<tr><td colspan="2"><strong>'. s($feedtitle) .'</strong></td></tr>'."\n";
 foreach ($rss->get_items() as $item) {
     echo '<tr><td valign="middle">'."\n";
-    echo '<a href="'. $item->get_link() .'" target="_blank"><strong>'. $item->get_title();
+    echo '<a href="'.$item->get_link().'" target="_blank"><strong>';
+    echo s($item->get_title());
     echo '</strong></a>'."\n";
     echo '</td>'."\n";
     echo '</tr>'."\n";
     echo '<tr><td colspan="2"><small>';
-    echo $item->get_description() .'</small></td></tr>'."\n";
+    echo format_text($item->get_description(), FORMAT_HTML) .'</small></td></tr>'."\n";
 }
 echo '</table>'."\n";
 
diff --git a/blog/renderer.php b/blog/renderer.php
index b605016d10e..af1724de1ab 100644
--- a/blog/renderer.php
+++ b/blog/renderer.php
@@ -119,11 +119,14 @@ class core_blog_renderer extends plugin_renderer_base {
         // Body.
         $o .= format_text($entry->summary, $entry->summaryformat, array('overflowdiv' => true));
 
-        // Uniquehash is used as a link to an external blog.
         if (!empty($entry->uniquehash)) {
-            $o .= $this->output->container_start('externalblog');
-            $o .= html_writer::link($entry->uniquehash, get_string('linktooriginalentry', 'blog'));
-            $o .= $this->output->container_end();
+            // Uniquehash is used as a link to an external blog.
+            $url = clean_param($entry->uniquehash, PARAM_URL);
+            if (!empty($url)) {
+                $o .= $this->output->container_start('externalblog');
+                $o .= html_writer::link($url, get_string('linktooriginalentry', 'blog'));
+                $o .= $this->output->container_end();
+            }
         }
 
         // Links to tags.