Problem: Using contextual links allows admins to have quick access to editing virtually any content on the site. In some cases, the cacheing system can get corrupted and display the Configure Block link in the Forum Topics Block and possibly others to unauthorized users.
Not to worry, this is not a vulnerability, as the page it links to just says you are unauthorized to view this page. It is however a nuisance and makes your site look bad.
The Fix: Clear your cache. In Drupal 7, login as admin. Goto Configuration > Performance and then clear the cache. Log back out and verify it is fixed.
This is known issue that is being tracked and should be fixed in a future update.
Guarding your IT Experience!