Apple has released the iOS 4.0.2 firmware for the iPhone and iPod touch and 3.2.2 for the iPad to patch a security exploit that was used by online jail break tool JailbreakMe.com.
Here’s the thing, though: this security patch won’t work on first-generation iPhone or iPod touch so these devices remain jailbroken and still at risk.
The security hole meant that PDF document with "maliciously crafted embedded fonts" could be read by an iPhone or iPod touch user that might then lead to arbitrary code execution.
Interestingly there is an (unofficial) fix for this if you want to keep your iPhone or iPod touch jailbroken but patch the security hole. It is being tested and should be released soon.
Jason Freeman, the guy behind the famous Cydia app store, has created the patch, which strangely enough looks like the only option for first-gen owners for now if they want to fix the security hole.