Apple has issued a security patch for its iPhone after criticism from researchers who uncovered the flaw.
But the firm has denied that hackers could take control of the devices using the text messaging vulnerability that the patch fixes.
Security researchers Charlie Miller and Collin Mulliner demonstrated the vulnerability at the Black Hat security conference in Las Vegas.
They charged that Apple had failed to issue a security patch for the vulnerability that could allow criminals to take control of iPhones using text messages.
Apple said in a statement that, contrary to reports, "No one has been able to take control of the iPhone to gain access to personal information using this exploit."
But within 24 hours Apple said on its support website, "Receiving a maliciously crafted SMS message may lead to an unexpected service interruption or arbitrary code execution."
Apple said the patch addresses the issue through improved error handling and credited Miller and Mulliner for reporting this issue.
iPhone users can install the security patch by connecting to Apple's iTunes store that has been set to update phones automatically.