I applied the patch SUPEE-6788 from 1.9.2.1 and had a issue with a catalog/navigation block type.
I have this in a CMS static block:
{{block type="catalog/navigation" name="categoryLandingPage" template="catalog/category/landing.phtml"}}
And it no longer shows that block; no errors in the log, or var/report folder.
I have other static blocks with the block type of core/template
and they are working fine. Right now, I think it has something to do with the APPSEC-1063 section of the patch.