Escape the output in wp_ajax_upload_attachment().

Props whyisjake, sstoqnov.

git-svn-id: https://develop.svn.wordpress.org/trunk@45936 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/async-upload.php

@@ -22,7 +22,7 @@
 
 require_once( ABSPATH . 'wp-admin/admin.php' );
 
-header( 'Content-Type: text/html; charset=' . get_option( 'blog_charset' ) );
+header( 'Content-Type: text/plain; charset=' . get_option( 'blog_charset' ) );
 
 if ( isset( $_REQUEST['action'] ) && 'upload-attachment' === $_REQUEST['action'] ) {
 	include( ABSPATH . 'wp-admin/includes/ajax-actions.php' );

src/wp-admin/includes/ajax-actions.php

@@ -2508,7 +2508,7 @@ function wp_ajax_upload_attachment() {
 				'success' => false,
 				'data'    => array(
 					'message'  => __( 'Sorry, you are not allowed to upload files.' ),
-					'filename' => $_FILES['async-upload']['name'],
+					'filename' => esc_html( $_FILES['async-upload']['name'] ),
 				),
 			)
 		);
@@ -2525,7 +2525,7 @@ function wp_ajax_upload_attachment() {
 					'success' => false,
 					'data'    => array(
 						'message'  => __( 'Sorry, you are not allowed to attach files to this post.' ),
-						'filename' => $_FILES['async-upload']['name'],
+						'filename' => esc_html( $_FILES['async-upload']['name'] ),
 					),
 				)
 			);
@@ -2552,7 +2552,7 @@ function wp_ajax_upload_attachment() {
 					'success' => false,
 					'data'    => array(
 						'message'  => __( 'The uploaded file is not a valid image. Please try again.' ),
-						'filename' => $_FILES['async-upload']['name'],
+						'filename' => esc_html( $_FILES['async-upload']['name'] ),
 					),
 				)
 			);
@@ -2569,7 +2569,7 @@ function wp_ajax_upload_attachment() {
 				'success' => false,
 				'data'    => array(
 					'message'  => $attachment_id->get_error_message(),
-					'filename' => $_FILES['async-upload']['name'],
+					'filename' => esc_html( $_FILES['async-upload']['name'] ),
 				),
 			)
 		);