Index: app/views/mailer/_issue_text_html.rhtml
===================================================================
--- app/views/mailer/_issue_text_html.rhtml	(revision 3434)
+++ app/views/mailer/_issue_text_html.rhtml	(working copy)
@@ -1,4 +1,4 @@
-<h1><%= link_to "#{issue.tracker.name} ##{issue.id}: #{issue.subject}", issue_url %></h1>
+<h1><%= link_to h("#{issue.tracker.name} ##{issue.id}: #{issue.subject}"), issue_url %></h1>
 
 <ul>
 <li><%=l(:field_author)%>: <%= issue.author %></li>