Index: wp-content/themes/twentythirteen/functions.php
===================================================================
--- wp-content/themes/twentythirteen/functions.php	(revision 54300)
+++ wp-content/themes/twentythirteen/functions.php	(working copy)
@@ -533,12 +533,12 @@
 
 		$categories_list = get_the_category_list( wp_get_list_item_separator() );
 		if ( $categories_list ) {
-			echo '<span class="categories-links">' . $categories_list . '</span>';
+			echo '<span class="categories-links">' . esc_html( $categories_list ) . '</span>';
 		}
 
 		$tags_list = get_the_tag_list( '', wp_get_list_item_separator() );
 		if ( $tags_list && ! is_wp_error( $tags_list ) ) {
-			echo '<span class="tags-links">' . $tags_list . '</span>';
+			echo '<span class="tags-links">' . esc_html( $tags_list ) . '</span>';
 		}
 
 		// Post author.