A new security release of Joomla 1.5 was published in End of July 2010: Joomla 1.5.20. An update is highly recommanded. The new version concerns mostly security aspects.
Meanwhile the bug announcement and communication about security lacks is well developed in the Joomla community, so there are fast reactions on new reports.

A new security release of Joomla 1.5 was published in End of July 2010: Joomla 1.5.20. An update is highly recommanded. The new version concerns mostly security aspects.
Meanwhile the bug announcement and communication about security lacks is well developed in the Joomla community, so there are fast reactions on new reports.
The content management system is increasingly popular - and a more attractive object for hackers.
Nevertheless: Using Joomla has more advantages because of its popularity: Special questions are not special enough to find support in one of the many worldwide active fores discussing Joomla.