If you are using the plugin WPTouch, you should be updating it immediately because of a vulnerability caught by the good folks at Sucuri. WPTouch is a great plugin for a mobile specific site, just make sure you are using the most current version that has patched the security vulnerability.
What is the vulnerability?
The vulnerability allows any logged in user (even subscribers to your site), the ability to upload any file to your site. The danger comes if a malicious person subscribes to your site, then uploads a file that can take over the use of your site.
What should you do?
If you are using WPTouch version 3.4.2 or lower, update to 3.4.3 as soon as possible.