Index: wp-admin/includes/class-wp-media-list-table.php
===================================================================
--- wp-admin/includes/class-wp-media-list-table.php	(revision 30983)
+++ wp-admin/includes/class-wp-media-list-table.php	(working copy)
@@ -75,7 +75,7 @@
 			if ( !empty( $_GET['attachment-filter'] ) && strpos( $_GET['attachment-filter'], 'post_mime_type:' ) === 0 && wp_match_mime_types( $mime_type, str_replace( 'post_mime_type:', '', $_GET['attachment-filter'] ) ) )
 				$selected = ' selected="selected"';
 			if ( !empty( $num_posts[$mime_type] ) )
-				$type_links[$mime_type] = '<option value="post_mime_type:' . sanitize_mime_type( $mime_type ) . '"' . $selected . '>' . sprintf( translate_nooped_plural( $label[2], $num_posts[$mime_type] ), number_format_i18n( $num_posts[$mime_type] )) . '</option>';
+				$type_links[$mime_type] = '<option value="post_mime_type:' . esc_attr( $mime_type ) . '"' . $selected . '>' . sprintf( translate_nooped_plural( $label[2], $num_posts[$mime_type] ), number_format_i18n( $num_posts[$mime_type] )) . '</option>';
 		}
 		$type_links['detached'] = '<option value="detached"' . ( $this->detached ? ' selected="selected"' : '' ) . '>' . sprintf( _nx( 'Unattached (%s)', 'Unattached (%s)', $total_orphans, 'detached files' ), number_format_i18n( $total_orphans ) ) . '</option>';
 
Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 30983)
+++ wp-includes/post.php	(working copy)
@@ -2478,11 +2478,13 @@
 	$wild = '[-._a-z0-9]*';
 
 	foreach ( (array) $wildcard_mime_types as $type ) {
-		$regex = str_replace( '__wildcard__', $wild, preg_quote( str_replace( '*', '__wildcard__', $type ) ) );
-		$patternses[1][$type] = "^$regex$";
-		if ( false === strpos($type, '/') ) {
-			$patternses[2][$type] = "^$regex/";
-			$patternses[3][$type] = $regex;
+		$mimes = array_map( 'trim', explode( ',', $type ) );
+		foreach ( $mimes as $mime ) {
+			$regex = str_replace( '__wildcard__', $wild, preg_quote( str_replace( '*', '__wildcard__', $mime ) ) );
+			$patternses[][$type] = "^$regex$";
+			if ( false === strpos($type, '/') ) {
+				$patternses[][$type] = "^$regex/";
+			}
 		}
 	}
 	asort( $patternses );