An official security warning for some versions of Apple's iPhone, iPad and iPod Touch has been issued by a German government agency.
The Federal Office for Information Security said Apple's iOS operating system has "two critical weak points for which no patch exists".
It said opening a manipulated website or PDF file could allow criminals to spy on passwords, planners and emails.
It said although no attacks have been observed yet they must be expected. Users should avoid opening PDF files, and never go to websites they do not trust, it added.
The warning relates to iPhones using iOS versions 3.1.2-4.0.1, iPads using iOS 3.2-3.2.1 and iPod Touches using iOS 3.1.2.-4.0.