Ticket #20009: 20009.3.diff

src/wp-includes/post-template.php

@@ -454 +454 @@
  */
 function post_class( $class = '', $post_id = null ) {
         // Separates classes with a single space, collates classes for post DIV.
-        echo 'class="' . join( ' ', get_post_class( $class, $post_id ) ) . '"';
+        echo 'class="' . esc_attr( join( ' ', get_post_class( $class, $post_id ) ) ) . '"';
 }
 
 /**
@@ -590 +590 @@
  */
 function body_class( $class = '' ) {
         // Separates class names with a single space, collates class names for body element.
-        echo 'class="' . join( ' ', get_body_class( $class ) ) . '"';
+        echo 'class="' . esc_attr( join( ' ', get_body_class( $class ) ) ) . '"';
 }
 
 /**