diff --git a/wp-includes/comment.php b/wp-includes/comment.php
index 9975158c74..7e078d92aa 100644
--- a/wp-includes/comment.php
+++ b/wp-includes/comment.php
@@ -1508,6 +1508,15 @@ function wp_update_comment($commentarr) {
 	if ( empty( $comment ) )
 		return 0;
 
+	$filter_comment = false;
+	if ( ! has_filter( 'pre_comment_content', 'wp_filter_kses' ) ) {
+		$filter_comment = ! user_can( isset( $comment['user_id'] ) ? $comment['user_id'] : 0, 'unfiltered_html' );
+	}
+
+	if ( $filter_comment ) {
+		add_filter( 'pre_comment_content', 'wp_filter_kses' );
+	}
+
 	// Escape data pulled from DB.
 	$comment = wp_slash($comment);
 
@@ -1518,6 +1527,10 @@ function wp_update_comment($commentarr) {
 
 	$commentarr = wp_filter_comment( $commentarr );
 
+	if ( $filter_comment ) {
+		remove_filter( 'pre_comment_content', 'wp_filter_kses' );
+	}
+
 	// Now extract the merged array.
 	extract(wp_unslash($commentarr), EXTR_SKIP);
 
diff --git a/wp-includes/default-widgets.php b/wp-includes/default-widgets.php
index 8074a07b7d..a8bad1aff5 100644
--- a/wp-includes/default-widgets.php
+++ b/wp-includes/default-widgets.php
@@ -834,7 +834,7 @@ function wp_widget_rss_output( $rss, $args = array() ) {
 
 	if ( is_wp_error($rss) ) {
 		if ( is_admin() || current_user_can('manage_options') )
-			echo '<p>' . sprintf( __('<strong>RSS Error</strong>: %s'), $rss->get_error_message() ) . '</p>';
+			echo '<p>' . sprintf( __('<strong>RSS Error</strong>: %s'), esc_html( $rss->get_error_message() ) ) . '</p>';
 		return;
 	}
 
@@ -942,7 +942,7 @@ function wp_widget_rss_form( $args, $inputs = null ) {
 	$show_date      = (int) $show_date;
 
 	if ( !empty($error) )
-		echo '<p class="widget-error"><strong>' . sprintf( __('RSS Error: %s'), $error) . '</strong></p>';
+		echo '<p class="widget-error"><strong>' . sprintf( __('RSS Error: %s'), esc_html( $error ) ) . '</strong></p>';
 
 	if ( $inputs['url'] ) :
 ?>
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 7b30fa4ad1..3e9603b1f5 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2221,8 +2221,16 @@ function wp_nonce_ays( $action ) {
 		$html .= sprintf( __( "Do you really want to <a href='%s'>log out</a>?"), wp_logout_url() );
 	} else {
 		$html = __( 'Are you sure you want to do this?' );
-		if ( wp_get_referer() )
-			$html .= "</p><p><a href='" . esc_url( remove_query_arg( 'updated', wp_get_referer() ) ) . "'>" . __( 'Please try again.' ) . "</a>";
+		if ( wp_get_referer() ) {
+			$wp_http_referer = remove_query_arg( 'updated', wp_get_referer() );
+			$wp_http_referer = wp_validate_redirect( esc_url_raw( $wp_http_referer ) );
+			$html .= '</p><p>';
+			$html .= sprintf(
+				'<a href="%s">%s</a>',
+				esc_url( $wp_http_referer ),
+				__( 'Please try again.' )
+			);
+		}
 	}
 
 	wp_die( $html, $title, array('response' => 403) );
diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index 6e8cd9a3c3..25f37788d0 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -313,6 +313,8 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
 	$phpmailer->ClearCCs();
 	$phpmailer->ClearCustomHeaders();
 	$phpmailer->ClearReplyTos();
+	$phpmailer->Body    = '';
+	$phpmailer->AltBody = '';
 
 	// From email and name
 	// If we don't have a name from the input headers
diff --git a/wp-mail.php b/wp-mail.php
index f1a12c5761..9d271b4fa4 100644
--- a/wp-mail.php
+++ b/wp-mail.php
@@ -56,6 +56,9 @@ if( 0 === $count ) {
 	wp_die( __('There doesn&#8217;t seem to be any new mail.') );
 }
 
+// Always run as an unauthenticated user.
+wp_set_current_user( 0 );
+
 for ( $i = 1; $i <= $count; $i++ ) {
 
 	$message = $pop3->get($i);
@@ -119,7 +122,6 @@ for ( $i = 1; $i <= $count; $i++ ) {
 					$author = trim($line);
 				$author = sanitize_email($author);
 				if ( is_email($author) ) {
-					echo '<p>' . sprintf(__('Author is %s'), $author) . '</p>';
 					$userdata = get_user_by('email', $author);
 					if ( ! empty( $userdata ) ) {
 						$post_author = $userdata->ID;
diff --git a/wp-trackback.php b/wp-trackback.php
index a93bab7c0e..e6a86b2ea2 100644
--- a/wp-trackback.php
+++ b/wp-trackback.php
@@ -13,6 +13,9 @@ if (empty($wp)) {
 	wp( array( 'tb' => '1' ) );
 }
 
+// Always run as an unauthenticated user.
+wp_set_current_user( 0 );
+
 /**
  * Response to a trackback.
  *