The same PDF vulnerability that Apple has patched in iOS 4.3.4 and iOS 4.2.9 can be patched with a free tweak available on the Cydia app store. After successfully jailbreaking your iPhone with JailbreakMe 3.0 simply follow these steps to close the security hole and read PDF files without worry.
1. Open Cydia and navigate to the Search tab.
2. Type pdf in the search field and results will appear.
3. Select PDF Patcher 2. The app screen will appear. You can scroll down for more information.