Joomla! 1.0.11
If you’re still runnning Joomla! 1.0.10 then you should immediately upgrade to Joomla! 1.0.11[Sunbird]
The latest version of Joomla! has a number of general bug fixes plus some low, medium and high level security patches which MUST be implemented in order for your Joomla! application to remain secure.