Hi,
Since this issue was published two days ago, our developers are inspecting this and we are doing some tests. However, it seems to be a general ASP.Net issue not related to Kentico
CMS and following the workaround described in the article should not affect any Kentico functionality (custom errors are set to "off" by default).
As soon as we will have any further information, we will publish a blog post on our DevNet portal (devnet.kentico.com).
Best regards,
Juraj Ondrus