Apple has shipped a patch to cover five documented vulnerabilities that expose iPhone and iPod Touch users to malicious hacker attacks. The most serious flaw could allow remote code execution if an iPhone/iPod Touch user opens audio and image files. The update is only available through iTunes and will not appear in the software update utility available in Mac and Windows systems. The vulnerabilities are being patched with this iPhone OS 3.1.3 and iPhone 3.2.3 for iPod Touch update: The update will only appear in iTunes.
Source: https://threatpost.com/apple-plugs-critical-iphone-security-holes-020210/73474/