First of all open up the command prompt (or SSH into your server if your applying the patch remotely). Change the current directory to your Magento store root folder (this is one of ours, you will need to change to suit):
cd /home/www/arrowdesign.co.uk
Just to be safe, run:
ls
To list the current directory structure, it should list files such as index.php, cron.php and get.php as well as directories such as app, skin, var etc. If these are not shown then you are probably in the wrong directory.
The above commands download the correct patch file from http://www.magentocommerce.com and store them in the current directory with the name CE_xxx.patch where xxx is the version it applies to.
It’s now time to patch Magento, run the following command (replacing xxx with the version number in your patch):
patch -p0 < CE_xxx.patch
This runs through the patch and applies the security updates to the affected files (lib/Zend/XmlRpc/Response.php and lib/Zend/XmlRpc/Request.php). You can then test the Magento store to ensure everything still works, if you need to you can reverse the patch using the following command:
patch -R -p0 < CE_xxx.patch
Once you are finished you can remove the patch file using the following command: