Joomla! 3.3.6 realese relates to the Joomla 3.3.5 released the day before. The latest version includes two security issues resolved concerning 3.3.5 version.
9 bugs in the latest Joomla! version have been fixed including problems like:
- Password reset don't work in Joomla 3.3.5
- Error when adding tags via keyboard
Security issues fixed:
- High Priority - Inadequate checking allowed the potential for remote files to be executed.
- Medium Priority - Inadequate checking allowed the potential for a denial of service attack.
Check more info here.