Apple devices can be hacked through a flaw in the way iOS 4 deals with PDF files, tech news site Gizmodo reported on Tuesday.
According to Gizmodo, the bug is capable of infecting all iOS 4-based Apple devices, and allows hackers to remotely control the device.
The bug can be exploited when a user visits a web address using Safari. The web browser can automatically load a PDF file containing a malicious code, hidden within a font, causing a stack overflow when displayed.
The stack overflow allows the bug to take complete control over the device as soon as the infected file is opened.
The bug may delete or transmit files in the device as well as install secret tracking software or make automatic calls to 911 from the iPhone.
Apple is yet to release a patch for the issue, but has advised people not to download a PDF file from an untrusted source, and to try and avoid visiting any PDF links directly.