Security flaw affects every version of Apple’s mobile OS. Hackers could use the flaw to send messages asking for personal information or direct users to phishing sites. Users would be under the impression they were replying to the sender displayed on the screen of their iPhone, when in fact the text would be routed through to a different number without their knowledge. The flaw has been present in Apple’s iPhone software ever since the first iPhone was launched in 2007, but has failed to have been picked up on by anybody, including Apple.
Source: https://thehackernews.com/2012/08/serious-security-flaw-iphone-bug-allows.html