While website Jailbreakme.com offers a one-click jailbreak for your iOS devices via mobile Safari, it also exposes a major security vulnerability. As it turns out, jailbreaking your iDevice may provide additional security options that make jailbreaking a more secure option.
Because jailbreakme is able to function through a PDF vulnerability in iOS and can be easily adapted for malicious attacks, loading a PDF through mobile Safari may pose a security risk for your iPhone, iPod touch or iPad. While no malicious exploits have currently been identified, it's worth being wary of PDFs while browsing the web on your iOS device. While not endorsing it, security company F-Secure's blog suggests a jailbreak app called PDF Loading Warner (search for it in Cydia if you're jailbroken), which will alert you when PDFs are loading to help protect you from loading one that could be malicious. Currently Apple is working on a patch with no specified release date, but in the meantime this may be your only way to add a little extra protection. (Just be sure to change your devices's ssh password if you do jailbreak.)
If you're looking to jailbreak, check out our post on jailbreakme for more information.