diff --git a/wp-admin/includes/media.php b/wp-admin/includes/media.php
index 0ae2f100ed..a30076996b 100644
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -392,10 +392,13 @@ function _media_button($title, $icon, $type, $id) {
 	return "<a href='" . esc_url( get_upload_iframe_src($type) ) . "' id='{$id}-add_{$type}' class='thickbox add_$type' title='" . esc_attr( $title ) . "'><img src='" . esc_url( admin_url( $icon ) ) . "' alt='$title' onclick='return false;' /></a>";
 }
 
-function get_upload_iframe_src( $type = null ) {
+function get_upload_iframe_src( $type = null, $post_id = null ) {
 	global $post_ID;
 
-	$uploading_iframe_ID = (int) $post_ID;
+	if ( empty( $post_id ) )
+		$post_id = $post_ID;
+
+	$uploading_iframe_ID = (int) $post_id;
 	$upload_iframe_src = add_query_arg( 'post_id', $uploading_iframe_ID, admin_url('media-upload.php') );
 
 	if ( $type && 'media' != $type )
diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index 252b056e9a..d2f26a6cfd 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -1152,7 +1152,7 @@ function _wp_post_thumbnail_html( $thumbnail_id = null, $post_id = null ) {
 	if ( empty( $post_id ) )
 		$post_id = $post_ID;
 
-	$set_thumbnail_link = '<p class="hide-if-no-js"><a title="' . esc_attr__( 'Set featured image' ) . '" href="' . esc_url( get_upload_iframe_src('image') ) . '" id="set-post-thumbnail" class="thickbox">%s</a></p>';
+	$set_thumbnail_link = '<p class="hide-if-no-js"><a title="' . esc_attr__( 'Set featured image' ) . '" href="' . esc_url( get_upload_iframe_src('image', $post_id) ) . '" id="set-post-thumbnail" class="thickbox">%s</a></p>';
 	$content = sprintf($set_thumbnail_link, esc_html__( 'Set featured image' ));
 
 	if ( $thumbnail_id && get_post( $thumbnail_id ) ) {