lib/PublicInbox/GzipFilter.pm | 3 ++-

diff --git a/lib/PublicInbox/GzipFilter.pm b/lib/PublicInbox/GzipFilter.pm
index b5ad9eb884cd7a57989b1ec1e9102f35d00bb826..f1354d2b7eb4e015a54aca61c129df1c70838ab4 100644
--- a/lib/PublicInbox/GzipFilter.pm
+++ b/lib/PublicInbox/GzipFilter.pm
@@ -165,7 +165,8 @@
 # this is public-inbox-httpd-specific
 sub async_blob_cb { # git->cat_async callback
 	my ($bref, $oid, $type, $size, $self) = @_;
-	my $http = $self->{env}->{'psgix.io'} or return; # client abort
+	my $http = $self->{env}->{'psgix.io'};
+	$http->{forward} or return; # client aborted
 	my $smsg = $self->{smsg} or bail($self, 'BUG: no smsg');
 	if (!defined($oid)) {
 		# it's possible to have TOCTOU if an admin runs