The issue is further explained @ https://www.drupal.org/SA-CORE-2016-005
sylus created an issue. See original summary.
Issue #2828594: Update Drupal Core to 7.52 (SA-CORE-2016-005)
Merge pull request #1889 from sylus/7.x-4.x
Issue #2828594: Update...
Automatically closed - issue fixed for 2 weeks with no activity.
Drupal is a registered trademark of Dries Buytaert.