lib/PublicInbox/MID.pm       |  1 +
 lib/PublicInbox/SearchMsg.pm |  2 +-
 t/mid.t                      | 11 +++++++++++
 t/nntpd.t                    | 17 ++++++++++-------

diff --git a/lib/PublicInbox/MID.pm b/lib/PublicInbox/MID.pm
index c82e84013ec0d68730423ab4b691074c5b690dc5..cd56f272613dc28551409593545eec5a2e80eb0e 100644
--- a/lib/PublicInbox/MID.pm
+++ b/lib/PublicInbox/MID.pm
@@ -87,6 +87,7 @@ 	my ($mids) = @_;
 	my @ret;
 	my %seen;
 	foreach my $mid (@$mids) {
+		$mid =~ tr/\n\t\r//d;
 		if (length($mid) > MAX_MID_SIZE) {
 			warn "Message-ID: <$mid> too long, truncating\n";
 			$mid = substr($mid, 0, MAX_MID_SIZE);
diff --git a/lib/PublicInbox/SearchMsg.pm b/lib/PublicInbox/SearchMsg.pm
index ab971e002d8a52846eaed9e83dacbab474e4f2d2..c7787ea1003db61221c6c2aa0d84ab41f60fd59d 100644
--- a/lib/PublicInbox/SearchMsg.pm
+++ b/lib/PublicInbox/SearchMsg.pm
@@ -100,7 +100,7 @@
 	my $mime = $self->{mime} or return;
 	$val = $mime->header($field);
 	$val = '' unless defined $val;
-	$val =~ tr/\n/ /;
+	$val =~ tr/\t\n/  /;
 	$val =~ tr/\r//d;
 	$self->{$field} = $val;
 }
diff --git a/t/mid.t b/t/mid.t
index 223be798c47704f7a1823e6f59037ead36c840c6..8c307c825d22a7e2747c8f35fb1df0909c798dcb 100644
--- a/t/mid.t
+++ b/t/mid.t
@@ -25,6 +25,17 @@ 	$mime->header_set('References', '<hello> <world>');
 	$mime->header_set('In-Reply-To', '<weld>');
 	is_deeply(['hello', 'world', 'weld'], references($mime->header_obj),
 		'references combines with In-Reply-To');
+
+	$mime->header_set('References', "<hello>\n\t<world>");
+	$mime->header_set('In-Reply-To');
+	is_deeply(references($mime->header_obj), ['hello', 'world'],
+		'multiline References OK');
+	$mime->header_set('References', "<hello\tworld>");
+	is_deeply(references($mime->header_obj), ['helloworld'],
+		'drop \t in References <656C30A1EFC89F6B2082D9B6@localhost>');
+	$mime->header_set('Message-ID', "<hello\tworld>");
+	is_deeply(mids($mime->header_obj), ['helloworld'],
+		'drop \t in Message-ID');
 }
 
 done_testing();
diff --git a/t/nntpd.t b/t/nntpd.t
index 3698f98baccc5d4f119d1dddda274700c75f494e..960e83c182868c4c74e5f08643fd62f394395606 100644
--- a/t/nntpd.t
+++ b/t/nntpd.t
@@ -80,9 +80,10 @@ From: =?utf-8?Q?El=C3=A9anor?= <me\@example.com>
 Cc: $addr
 Message-Id: <nntp\@example.com>
 Content-Type: text/plain; charset=utf-8
-Subject: Testing for =?utf-8?Q?El=C3=A9anor?=
+Subject: Testing for	=?utf-8?Q?El=C3=A9anor?=
 Date: Thu, 01 Jan 1970 06:06:06 +0000
 Content-Transfer-Encoding: 8bit
+References: <ref	tab	squeezed>
 
 This is a test message for El\xc3\xa9anor
 EOF
@@ -139,7 +140,8 @@ 		'date' => 'Thu, 01 Jan 1970 06:06:06 +0000',
 		'from' => "El\xc3\xa9anor <me\@example.com>",
 		'to' => "El\xc3\xa9anor <you\@example.com>",
 		'cc' => $addr,
-		'xref' => "example.com $group:1"
+		'xref' => "example.com $group:1",
+		'references' => '<reftabsqueezed>',
 	);
 
 	my $s = IO::Socket::INET->new(%opts);
@@ -189,7 +191,7 @@ 		'1' => ["Testing for El\xc3\xa9anor",
 			"El\xc3\xa9anor <me\@example.com>",
 			'Thu, 01 Jan 1970 06:06:06 +0000',
 			'<nntp@example.com>',
-			'',
+			'<reftabsqueezed>',
 			$len,
 			'1' ] }, "XOVER range works");
 
@@ -198,7 +200,7 @@ 		'1' => ["Testing for El\xc3\xa9anor",
 			"El\xc3\xa9anor <me\@example.com>",
 			'Thu, 01 Jan 1970 06:06:06 +0000',
 			'<nntp@example.com>',
-			'',
+			'<reftabsqueezed>',
 			$len,
 			'1' ] }, "XOVER by article works");
 
@@ -220,14 +222,15 @@ 		like($r[0], qr/^224 /, 'got 224 response for OVER');
 		is($r[1], "0\tTesting for El\xc3\xa9anor\t" .
 			"El\xc3\xa9anor <me\@example.com>\t" .
 			"Thu, 01 Jan 1970 06:06:06 +0000\t" .
-			"$mid\t\t$len\t1", 'OVER by Message-ID works');
+			"$mid\t<reftabsqueezed>\t$len\t1",
+			'OVER by Message-ID works');
 		is($r[2], '.', 'correctly terminated response');
 	}
 
 	is_deeply($n->xhdr(qw(Cc 1-)), { 1 => 'test-nntpd@example.com' },
 		 'XHDR Cc 1- works');
-	is_deeply($n->xhdr(qw(References 1-)), { 1 => '' },
-		 'XHDR References 1- works (empty string)');
+	is_deeply($n->xhdr(qw(References 1-)), { 1 => '<reftabsqueezed>' },
+		 'XHDR References 1- works)');
 	is_deeply($n->xhdr(qw(list-id 1-)), {},
 		 'XHDR on invalid header returns empty');