Index: src/wp-includes/class-wp-editor.php
===================================================================
--- src/wp-includes/class-wp-editor.php	(revision 39351)
+++ src/wp-includes/class-wp-editor.php	(working copy)
@@ -560,6 +560,8 @@
 					'plugins' => implode( ',', $plugins ),
 					'wp_lang_attr' => get_bloginfo( 'language' ),
 					'wp_shortcut_labels' => wp_json_encode( $shortcut_labels ),
+					'rest_url' => rest_url( '/wp/v2/posts' ),
+					'rest_nonce' => wp_create_nonce( 'wp_rest' )
 				);
 
 				if ( ! empty( $mce_external_plugins ) ) {
@@ -1111,7 +1113,7 @@
 		}
 
 		$mce_translation = self::get_translation();
-		
+
 		foreach ( $mce_translation as $name => $value ) {
 			if ( is_array( $value ) ) {
 				$mce_translation[$name] = $value[0];
Index: src/wp-includes/js/tinymce/plugins/wplink/plugin.js
===================================================================
--- src/wp-includes/js/tinymce/plugins/wplink/plugin.js	(revision 39351)
+++ src/wp-includes/js/tinymce/plugins/wplink/plugin.js	(working copy)
@@ -405,11 +405,11 @@
 								return response();
 							}
 
-							$.post( window.ajaxurl, {
+							$.get( editor.settings.rest_url, {
 								action: 'wp-link-ajax',
 								page: 1,
 								search: request.term,
-								_ajax_linking_nonce: $( '#_ajax_linking_nonce' ).val()
+								_wp_nonce: editor.settings.rest_nonce
 							}, function( data ) {
 								cache = data;
 								response( data );
@@ -426,7 +426,7 @@
 							event.preventDefault();
 						},
 						select: function( event, ui ) {
-							$input.val( ui.item.permalink );
+							$input.val( ui.item.link );
 							$( element.firstChild.nextSibling ).val( ui.item.title );
 
 							if ( 9 === event.keyCode && typeof window.wpLinkL10n !== 'undefined' ) {
@@ -461,8 +461,8 @@
 							}
 						}
 					} ).autocomplete( 'instance' )._renderItem = function( ul, item ) {
-						return $( '<li role="option" id="mce-wp-autocomplete-' + item.ID + '">' )
-						.append( '<span>' + item.title + '</span>&nbsp;<span class="wp-editor-float-right">' + item.info + '</span>' )
+						return $( '<li role="option" id="mce-wp-autocomplete-' + item.id + '">' )
+						.append( '<span>' + item.title.rendered + '</span>&nbsp;<span class="wp-editor-float-right">' + item.date + '</span>' )
 						.appendTo( ul );
 					};