Apple has fixed a major security flaw affecting iPhones - and says it's going to compensate the teenager who discovered the issue.

Last week, it emerged that a bug allowed iPhone users to eavesdrop on people they were calling on FaceTime group chat, even if they did not pick up the phone.

It prompted Apple to disable the Group FaceTime feature temporarily.

The tech giant has now released an update for its iOS 12 operating system to fix the issue, and is advising all users to install the new software.

In its update notes, the company credited Grant Thompson of Catalina Foothills High School in Arizona for discovering the bug, as well as Daven Morris of Arlington, TX.

Grant stumbled on the bug last month while calling his friends to play the video game Fortnite.

Reuters reports that Apple has confirmed it will compensate the Thompson family, as well as making a contribution towards 14-year-old Grant's education.

Further details of the payments have not been revealed.

Despite fixing the flaw, Apple is continuing to face questions over its handling of the issue.

Earlier this week, two senior Democrats in the US House of Representatives wrote to the company's CEO Tim Cook asking for more information about the bug - including over when the tech giant found out about it.

Frank Pallone, Jr and Jan Schakowsky of the House Committee on Energy & Commerce wrote: "As a first step, we believe it is important for Apple to be transparent about its investigation into the Group FaceTime vulnerability and the steps it is taking to protect consumers’ privacy.

"To date, we do not believe Apple has been as transparent as this serious issue requires."