lib/PublicInbox/EmlContentFoo.pm | 2 +-

diff --git a/lib/PublicInbox/EmlContentFoo.pm b/lib/PublicInbox/EmlContentFoo.pm
index 7472f8d24fc6f3ad2ff4abd9255b58ad7717e148..e6005d290c933b1575bdc795123b6c1ae67ccc79 100644
--- a/lib/PublicInbox/EmlContentFoo.pm
+++ b/lib/PublicInbox/EmlContentFoo.pm
@@ -190,7 +190,7 @@ 	}
 	foreach (keys %{$attribs}) {
 		next unless $_ =~ m/^(.*)\*$/;
 		my $key = $1;
-		next unless $attribs->{$_} =~ m/^$re_exvalue$/;
+		next unless ($attribs->{$_} // '') =~ m/^$re_exvalue$/;
 		my ($charset, $value) = ($1, $2);
 		$value =~ s/%([0-9A-Fa-f]{2})/pack('C', hex($1))/eg;
 		if (length $charset) {