diff -Naur warden-server-2.1/warden-server/lib/Warden.pm warden-server-2.1.new/warden-server/lib/Warden.pm
--- warden-server-2.1/warden-server/lib/Warden.pm	2013-09-10 12:08:12.000000000 +0200
+++ warden-server-2.1.new/warden-server/lib/Warden.pm	2014-10-16 14:27:07.000000000 +0200
@@ -102,9 +102,11 @@
   my $der = decode_base64(join("", @a));
   my $decoded= Crypt::X509->new(cert => $der);
 
-  foreach my $tmp (@{$decoded->SubjectAltName}) {
-    if($tmp =~ s/dNSName=//){
-      push(@an_array, $DBH->quote($tmp));
+  if (defined $decoded->SubjectAltName) {
+    foreach my $tmp (@{$decoded->SubjectAltName}) {
+      if($tmp =~ s/dNSName=//){
+        push(@an_array, $DBH->quote($tmp));
+      }
     }
   }
   my $alt_names = join(',', @an_array);