Index: src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
===================================================================
--- src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php	(revision 39085)
+++ src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php	(working copy)
@@ -1132,6 +1132,9 @@
 					'description'     => __( 'The content for the object.' ),
 					'type'            => 'object',
 					'context'         => array( 'view', 'edit', 'embed' ),
+					'arg_options'     => array(
+						'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database()
+					),
 					'properties'      => array(
 						'raw'         => array(
 							'description'     => __( 'Content for the object, as it exists in the database.' ),
Index: src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
===================================================================
--- src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php	(revision 39085)
+++ src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php	(working copy)
@@ -1813,6 +1813,9 @@
 						'description' => __( 'The title for the object.' ),
 						'type'        => 'object',
 						'context'     => array( 'view', 'edit', 'embed' ),
+						'arg_options' => array(
+							'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database()
+						),
 						'properties'  => array(
 							'raw' => array(
 								'description' => __( 'Title for the object, as it exists in the database.' ),
@@ -1834,6 +1837,9 @@
 						'description' => __( 'The content for the object.' ),
 						'type'        => 'object',
 						'context'     => array( 'view', 'edit' ),
+						'arg_options' => array(
+							'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database()
+						),
 						'properties'  => array(
 							'raw' => array(
 								'description' => __( 'Content for the object, as it exists in the database.' ),
@@ -1869,6 +1875,9 @@
 						'description' => __( 'The excerpt for the object.' ),
 						'type'        => 'object',
 						'context'     => array( 'view', 'edit', 'embed' ),
+						'arg_options' => array(
+							'sanitize_callback' => null, // Note: sanitization implemented in self::prepare_item_for_database()
+						),
 						'properties'  => array(
 							'raw' => array(
 								'description' => __( 'Excerpt for the object, as it exists in the database.' ),