Hi,
We don't plan to add that updated version to the current releases (5.5 R2) of Kentico CMS.
The bug descriptions says:
The vulnerability is caused due to an error in the handling of file uploads in editor/filemanager/upload/php/upload.php when a filename has multiple file extensions.It is a fix for some FCKeditor default script, which is not used in Kentico
CMS port, so it shouldn't have any influence on the security.
The infinite loop issue has not been reported yet, it seems to appear only in special cases as well.
If you're experiencing any of the issues, please let us know.
Regards,
Zdenek Cetkovsky