Credits to Tehnoon Raza
The September Security Bulletin will have SharePoint security updates with a security rating of “Important”.
Both 2007 and 2010 versions will be affected including Office Web Apps. When updates are pushed out to servers without the administrators noticing, this can cause SharePoint to stop working because the updates
are installed but not running PSConfig afterwards.
PSConfig must be run after update installations!
The known issues in short:
SharePoint 2010 Issues:
Issue #1- Users unable to browse Publishing sites
Issue #2- Unable to Manage User Profile Service Application
For more details and also for information on current known issues related to the security updates, please visit Tehnoon’s excellent post here!
Complete summary of all known issues affecting SharePoint 2010 and MOSS 2007 are described in the kb article 2451858.
Find also some updates and Info's on my fellows blog,
"Update on September Security Bulletin (MS11-074) and SharePoint 2010 Issues", by Stefan Goßner