diff --git a/src/wp-admin/includes/ajax-actions.php b/src/wp-admin/includes/ajax-actions.php
index 734409fe1f..82d8abc27f 100644
--- a/src/wp-admin/includes/ajax-actions.php
+++ b/src/wp-admin/includes/ajax-actions.php
@@ -241,10 +241,11 @@ function wp_ajax_logged_in() {
  * @return die
  */
 function _wp_ajax_delete_comment_response( $comment_id, $delta = -1 ) {
-	$total = (int) @$_POST['_total'];
-	$per_page = (int) @$_POST['_per_page'];
-	$page = (int) @$_POST['_page'];
-	$url = esc_url_raw( @$_POST['_url'] );
+	$total    = isset( $_POST['_total'] )    ? (int) $_POST['_total']    : 0;
+	$per_page = isset( $_POST['_per_page'] ) ? (int) $_POST['_per_page'] : 0;
+	$page     = isset( $_POST['_page'] )     ? (int) $_POST['_page']     : 0;
+	$url      = isset( $_POST['_url'] )      ? esc_url_raw( $_POST['_url'] ) : '';
+
 	// JS didn't send us everything we need to know. Just die with success message
 	if ( !$total || !$per_page || !$page || !$url )
 		wp_die( time() );
diff --git a/src/wp-admin/includes/media.php b/src/wp-admin/includes/media.php
index 4b6417f861..c37dc0b1c4 100644
--- a/src/wp-admin/includes/media.php
+++ b/src/wp-admin/includes/media.php
@@ -2077,17 +2077,18 @@ $arc_query = "SELECT DISTINCT YEAR(post_date) AS yyear, MONTH(post_date) AS mmon
 $arc_result = $wpdb->get_results( $arc_query );
 
 $month_count = count($arc_result);
+$selected_month = isset( $_GET['m'] ) ? $_GET['m'] : 0;
 
 if ( $month_count && !( 1 == $month_count && 0 == $arc_result[0]->mmonth ) ) { ?>
 <select name='m'>
-<option<?php selected( @$_GET['m'], 0 ); ?> value='0'><?php _e('Show all dates'); ?></option>
+<option<?php selected( $selected_month, 0 ); ?> value='0'><?php _e('Show all dates'); ?></option>
 <?php
 foreach ($arc_result as $arc_row) {
 	if ( $arc_row->yyear == 0 )
 		continue;
 	$arc_row->mmonth = zeroise( $arc_row->mmonth, 2 );
 
-	if ( isset($_GET['m']) && ( $arc_row->yyear . $arc_row->mmonth == $_GET['m'] ) )
+	if ( $arc_row->yyear . $arc_row->mmonth == $selected_month )
 		$default = ' selected="selected"';
 	else
 		$default = '';
diff --git a/src/wp-includes/theme.php b/src/wp-includes/theme.php
index 68863a382a..49049dbdbd 100644
--- a/src/wp-includes/theme.php
+++ b/src/wp-includes/theme.php
@@ -647,7 +647,10 @@ function preview_theme_ob_filter_callback( $matches ) {
 	)
 		return $matches[1] . "#$matches[2] onclick=$matches[2]return false;" . $matches[4];
 
-	$link = add_query_arg( array( 'preview' => 1, 'template' => $_GET['template'], 'stylesheet' => @$_GET['stylesheet'], 'preview_iframe' => 1 ), $matches[3] );
+	$stylesheet = isset( $_GET['stylesheet'] ) ? $_GET['stylesheet'] : '';
+	$template   = isset( $_GET['template'] )   ? $_GET['template']   : '';
+
+	$link = add_query_arg( array( 'preview' => 1, 'template' => $template, 'stylesheet' => $stylesheet, 'preview_iframe' => 1 ), $matches[3] );
 	if ( 0 === strpos($link, 'preview=1') )
 		$link = "?$link";
 	return $matches[1] . esc_attr( $link ) . $matches[4];