SAN FRANCISCO - JUNE 07: An attendee inspects the new iPhone 4 at the 2010 Apple World Wide Developers conference June 7, 2010 in San Francisco, California. Apple CEO Steve Jobs kicked off their annual WWDC with the announcement of the new iPhone 4.. (Photo by Justin Sullivan/Getty Images)
Hackers could gain access to data stored on Apple Inc.'s gadgets by putting a PDF file with hidden code onto a website and luring people to visit the site.
Apple did not say when the software update will be available.
The flaw drew attention after it was used for a program that lets people "jailbreak" iPhones in order to run programs Apple hasn't approved for sale in its iTunes store.
The company declined to say Thursday whether it knows of malicious hackers actively exploiting the flaw.
A German government agency issued an official warning about the flaw Wednesday.