Recently, important updates were released for Joomla 2.5 and Joomla 3.1 that address a critical security issue where unauthorized file uploads may be uploaded to a site.

Joomla 1.5 is affected by a security vulnerability "unauthorized file uploads". Joomla 1.5 has reached it's end-of-life and no update is being released for it.

To apply the security patch:

  1. If the site is currently at Joomla 1.5.26 proceed to step 2. If not upgrade your site to the latest stable version of Joomla 1.5 using this update package.
  2. Download the Security Patch attached to this article
  3. Log into your Joomla 1.5 administration panel
  4. Select Extensions > Install/Uninstall > Choose File > Upload & Install 

The installer cleans up after itself, leaving only the files that the patch replaces.