Before you go ahead with the jailbreak, make sure to have a backup of your iDevice through iTunes – just in case something goes wrong.
This jailbreak works by exploiting a security hole in Safari when it comes to displaying PDF files. In theory, malicious websites could do something similar and get access to your iPhone – but how much access they can get and what data they have access to, I’m not sure of. It’s likely that Apple will release a software update to patch this hole in the near future, so this jailbreak will probably not work on future software versions of iOS.
Here’s how JailbreakMe 2.0 works: