Apple has released iOS 4.3.5, which fixes “a security vulnerability with certificate validation.” To update to the latest operating system, plug your iOS device into iTunes and follow the prompts.
Actually, the 4.3.5 update applies to the iPad and iPad 2, the third- and fourth-generation iPod touch, the iPhone 3GS, and the iPhone 4 (GSM model). Version 4.2.10 is for those using a CDMA (Verizon) iPhone 4.