diff --git a/FU.pm b/FU.pm
index f1493a7..002fec3 100644
--- a/FU.pm
+++ b/FU.pm
@@ -705,7 +705,8 @@ sub cookie {
         my %c;
         for my $c (split /; /, fu->header('cookie')||'') {
             my($n, $v) = split /=/, $c, 2;
-            if (!exists $c{$n}) { $c{$n} = $v }
+            if (!defined $v) {}
+            elsif (!exists $c{$n}) { $c{$n} = $v }
             elsif (ref $c{$n}) { push $c{$n}->@*, $v }
             else { $c{$n} = [ $c{$n}, $v ] }
         }